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Mejor professor

Date )27 {Zia/Z _

THE EFFECT OF SMALL AMOUNTS OF AZTIMONY
ON THE TRAFSFORMATION AND PROPERTIES OF

ALUMINUM

by

ARTHUR JAMES STONE

W

A THESIS
Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirement:
for the degree of

MASTER OF SCIENCE

Department of Chemical and Metallurgical Engineering
1947

lHESus

 

2».

I.
II.
III.
IV.

VI.

VII.

VIII.
IX.

XI.

TABLE OF CONTENTS
Title Page ..................................
Table of Contents ...........................
Acknowledgement .............................
Introduction ................................
An Investigation of the Equilibrium Diagram

General Theory OOOOOOOOOOOOOOOOOOOOOOO
Materials and Apparatus ..............
ThermocouplI Calibration eeeeeeee.eeee
Emeeduro .COOOOOOOOOOOOOOOOCOOOOOOOCC
T‘bUlated Datfi eeeeeeeeeeeeeeeeeeeeeee
Discussion ...........................

The Mierostructure of the Alloys

General Theory .......................
Procedure OOOOOOOOOOOOOOOOO00.0.0.0...
Microetructure .......................
Discussion ...........................

Chemical Analysis

Introduction .........................
’ Procedure ............................
Tabulated Data .......................
Di'cu3'10n eeeeeeeeeeeeeeeeeeeeeeeeeee

Proposed Equilibrium Diagram ................

An Examination of the Physical PrOperties
Intmdu.t1°n OOOOOOOOOOOOOOOOOOOOO0.0.
Materials and Apparatus ..............
Proeodur. eeeeeeeeeeeeeeeeeeeeeeeeeeee
Physieal Testing Data ................
Discussion ...........................

concIUBIOn OeOOeoeeeeeeeeeeeeeeeeeeeeeeeeeeee

R.f.r.ne.. ‘COOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

I‘. -’“‘ {'3 "" I ‘y
-' «L ,V, -. ,- e‘ '
g..itauldxhtt)

#‘ \H ID #4

15
22
23
47

49 '
50
58

6O
61
63
64

65

70
71
72
74
75

80
83

ACKNOWLEDGEMEET
The author is indebted to Mr. Robert L.
Sweet and Mr. D.D. McGrady for their assistance,
advice and guidance. The author also wishes to
eXpress his appreciation to Mr. H.L. Womochel
for his advice, for the use of the Mechanical
Engineering Research Chemistry Laboratory and

for the machining of the physical test bars.

.1!- INTRODUCTION

The effects of antimony upon the physical prop-
erties of aluminum and aluminum alloys are not generally
known. However, it has been believed that the effects are
detrimental. Small additions of antimony to aluminum-
magnesium alloys were used at one time. At that time, it
was claimed that the formation of antimony oxychloride
caused good resistance to corrosion of these alloys, but
it has been proven that aluminum-magnesium alloys have
good corrosion resistance without the antimony additions.
Additions of antimony are sometimes used in other alum-
inum alloys, but the reasons are seldom clear.

The main objective of the investigation was to he
a study of the physical properties of additions of 1% or
less antimony to aluminum. A survey of the literature for
an appropriate equilibrium diagram was made. Upon dis—
covering that there were several diagrams, none of which
agreed, it was thought that an accurate equilibrium
diagram would be a valuable addition to the literature and
also would be necessary to the completion of the original
investigation.

or the several diagrams published, three are
reproduced in this report, shown in figures 1,2 and 3.
Those reproduced are the equilibrium diagrams published

. l 2
by Dowdell, Jerabek, Forsyth, Green ; Mondolfo ; and in

3
the International Critical Tables . Of those published,

Itxkkndiu

 

Q
g’fi10)___ _ _’l

'0‘

VI,

 

'9 e. 739214224”. I

\(Qxin \(00

 

the one by Mondolfo, taken from data by Guerther and
Bergmann, Owen and Preston, and Dix and colleagues, is the
most explicit. It also is the only diagram describing the
0-1% antimony region of the diagram to any great degree.

Mondolfoestates that the solid solubility of anti-
mony in aluminum is limited . It is less than 0.10% anti-
mony at the eutectic temperature 657°C(1215°F.). Aluminum
and antimony form a face-centered cubic compound SbAl. A
eutectic Al-SbAl exists at about 1.1% antimony-melting
point 657°C(1215°F.). Then the solidification temperature
rises until at 81.6% antimony it reaches 1050°C(1922°F.),
corresponding to the compound SbAl. From there on, the
freezing point drops until at 100% antimony it reaches
630°C(1166°F.), for the eutectic Sb-SbAl practically
corresponds to pure antimony.

The freezing point of pure aluminum is 1214.6OF.4
and Mondolfo states that two eutectics,0.10% antimony and
1.1% antimony, melt at 12150F. However possible, these
facts seemed suspicious. Nor does this description explain
the shapa or position of the liquidus or solidus in the
necessary region of the diagram. Therefore, it could not
be used in any study of the physical properties of the
alloys investigated.

Consequently, it was deemed necessary to attempt to
construct a more accurate diagram for the region investi-

gatede

v. Ag INVESTIGATION pg THE EQUILIBRIUM DIAGRAM

 

GENERAL THEORY

 

Before outlining the specific properties which
would tend to show what may be expected in the nature of
an equilibrium diagram for additions of antimony to
relatively pure aluminum, perhaps it would be well to
repeat a few general characteristics of all additions of
one metal to another to form alloys.

From the standpoint Of crystal structure, solid
solution alloys may be divided into two main classes,
called, substitutional and interstitial types. The struc-
ture of any phase of the first may be viewed as though
derived from a lattice of one of the constituents by
replacing some of the atoms of this metal with atoms of the
alloying metal. Therefore, as the composition is varied
within the solubility limits of a given phase of a sub-
stitutional alloy, the variation takes place by the replace-
ment of one kind of atom by the other. In interstitial
alloys, one or more of the constituent atoms enter into the
interstitial positions of another metal.

Since only four interstitial atoms namely hydrogen,
carbon, nitrogen, and boron, are small enough to satisfy the
conditions of an interstitial alloys, the requirements for
interstitial alloys will not be stated further.

Carapella6 states that the extent to which atoms of
solute replace atoms of solvent on the solvent lattice is

termed solid solubility.

10

The type of crystal structure influences this
factor. Complete solid solubility can only be expected
with like crystal structure, provided all other factors
are favorable. Metals with other crystal structures can-
not form complete solid solutions with the solvent, for,
by their very nature, they introduce at least one phase
to the system that is not of the same crystal structure as
the solvent.

there the atomic sizes of the solvent and solute
metals differ by less than 15%, the size factor is favor -
able 5,6. If the diIIerences of atomic sizes exceed this
limit the solubility is restricted. In fact, the greater
the difference in size, the more restricted is the solu--
bility if other factors are equal. Solute atoms which
have atomic sizes Just on the edge of the favorable zone
tend to give erratic results. Moreover, if the atomic
sizes differ by more than 8%, but still in the favorable
zone, there is usually a minimum in the liquidus curves
representing a definite tendency toward eutectic formation.

The more electropositive the solvent metal the more
electronegative the solute metal, or visa versa, the
greater the tendency to restrict solid solubility and to
form intermetallic compounds 6. The electronegative degree
Of metals in the perodic system of chemical compounds
increases from left to right in any period and bottom
to top in any group. That is, for wide ranges of com-

position, elements which alloy well lie near one another

L1

in the electromotive series as well as having nearly
equal.radii.

A general trend, where size factor is favorable,
is for solvent solutions to become more restricted as
the valencies become more unequal6. Furthermore, the
more unequal the valency factor, the steeper is the drop
in both the liquidus and solidus curves.

As has been shown, crystallographic structure, size
factor, the electronegative degree and the valencies of
the metals in the alloy each tend to influence the limit
of solid solubility, formation of intermetallic comp
pounds and general shape of the liquidus and solidus in
the equilibrium diagram.

Aluminum and antimony have very different crystal
structure. Aluminum has a face—centered cubic lattice while
antimony has a rhombohedral hexagonal. Thus aluminum and
antimony cannot have much solubility.

The atomic diameters of aluminum and antimony
vary by approximately 1%, antimony being slightly largers.
This factor does not restrict solubility nor does it
cause a minimum in the liquidus curve.

Aluminum lies higher in the electromotive series
than antimony. In fact, in the formation of intermetallie
compounds, antimony is considered electronegative and
aluminum electropositive5. This fact would tend to prevent
solid solubility and cause the probability of the form-

ation of intermetallic compounds.

12

Aluminum has a valence of three and antimony has
a valence of three, four, or five, although three generally
predominates. The fact that the valencies are generally
the same favors formation of solid solution. Furthermore,
this fact tends to flatten the liquidus and solidus curves.
With the foregoing facts in mind, a very restricted
region of solid solubility, one or more intermetallic
compounds, and a gradual lepe of liq uidus and solidus

curves should be expected.

13

MATERIALS AND APPARATUS

 

A HosKins Furnace, Type FA120, with a resistance
type heating coil, having a capacity of 100 volts and 3.5
Amperes was used for melting the alloys. The aluminum used
was from ingot 5 with impurities as shown in Taole l. The
antimony added to the aluminum was listed as commercially
pure. Since only tenths of a percent were added, it was
thought that the small amounts of impurities would be
negligible. An iron-constantan thermocouple of 24 BhS
gauge wire was used, with melting ice in a vacuum flask
as a cold-junction. A Leeds and Northrup "K“ type poten-
tiometer, with its galvanometer, light source and scale,
was used to take the temperature readings. These readings
were accurate to 1.01 mv. A single stop-watch was used
for reading time and when once started was allowed to run
to the completion of the test run. These time readings
were accurate to the nearest 5 sec.

The rate of heating or cooling was controlled
by the addition of external resistance and an ammeter
and voltmeter were added as shown in Fig. 4, to the
circuit to prevent overloading the furnace.

The melting was done in a sealed alundum thin

shell crucible, 1%"D X 4", as shown in Fig. 5.

(Analyzed By SpeEIrographic Methods)

Ingot#

Ul-P'UNH

TABLE g

14

COMPOSITION OF ALUMINUM USED

 

93
.01 t
N

 

(By Percent)

 

Es .12. .122
race
N .15 W
" .14 '
u .15 N
W .14 i.
TABLE

21418

.21 trace .002

1

e13 tra.

.12
.12
.12
.14

ALLOY COMPOSITIONS

 

Al

ce balance
0|

Impurities Subtracted from Aluminum

my

.05
.10
.20
.30
.40
.50
.60
.70
.80
.90
1.00
1.10

(By Weight)

 

 

III-ii III-.512
In Grams In Grams
85.0112 .0425
79.8475 .0798
88.3837 .1768
77.8697 .2336
69.5252 .2771
87.7758 .4389
70.6842 .4241
76.2426 .5337
80.7050 .6456
86.1890 .7757
92.9969 .9300
74.0836 .8149
TABLE‘;;;
QINC ANALYSIS
Insoluble
in H2304 -,.O2%
As — .000001
Pb a .005
Fe - .003
Total - .028001

 

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Fla .4" gag!” or 77/! Gees/546;. affix/M2 7’1;
Poe; 12241 gr ffli .41 ant/”VA! 4W

16

THERMOCOUPLE CALIBRATION

Before making any test runs for cooling curves,
it was necessary to calibrate the iron-constantan thermo—
couple.

The most important temperature range for inves-
tigation of the alloys chosen was the range from 700°F.
to 14000F. Therefore, zinc with a melting point of 787°F.
and pure aluminum with a melting point of 1214.60F. were
chosen to calibrate the thermocouple. The zinc analysis
is shown in Table 3. The aluminum used was from ingot 5,
with an analysis as shown in Table 1.

The cooling curves were made using the same pro-
ced ure as that described in the following section. The
results were as shown in Figures 6 and 7.

The thermocouple bead was covered with alundum
cement. This covering was made as thin as possible to
eliminate a my hysteresis that might be caused by this
covering. The thermocouple, with the exception of this
bead, was covered with refractory tubing, commonly called
"spagetti", two inches beyond the furnace. The wires were
spread from there to the cold-junction to prevent any short
to the system.

From the results shown it was agreed that the thermo—
couple was accurate within the probable error Of the other
equipment, which.was less than .03%.

After calibrating the thermocouple, a heating and

l7

cooling curve of the furnace were run. It was found that
when holding the voltage of the furnace at 73 volts the
temperature of 1000°F. could be held for an hour, once
the temperature was reached.

It was decided, therefore, when running a heating
curve, to maintain the voltage at 83-85 volts and when

running a cooling curve, to maintain 63-65 volts.

 

18

 

l9

 

20

DATA FOR THERMOCOUPLE CALIBRATION

papa for the transformation of zinc from

TABLE II ._
liguid 32 solid and solid 39 liguid. (Figure 6)—

MVe

23.24
23.13
22.96
22.90
22.88
22.87
22.855
22.85
22.83
22.76
22.70
22.50
22.505
22.405
22.305

Cooling

1111112

0'00“
55" ‘
1150"
2'45"
3I45fl
5'45"
9'45"
18'20"
24' so"
27 O 25"
29 to"
3010"
30'5030
31' 25"
320 o"

 

22.45
22.56
22.66
22.72
22 e76
22.78
22 e82
22.85
22.86
22.875
22.89
22.91
22.93
22.98
23.03
23.13
23.23

heating

Ilsa

0'00"
50"
1145"
2'45"
3'45"
4'45"
615"
8'15"
11'40"
20'15"
24' 15"
25'45"
26'15"
26 ' 50"
27'27"
28'12"
29' 2"

 

21

TABLE y Data for the transformation of alumingm from
quuid‘tg aoIid and aoIIE E3 IIquIa. TFiguréfII

 

 

29.2.1.er 212213.; .8n
82° 1282 .1282 22 81- .2322 2282 EE
Tomg. Temp.
37.50 30’10" 20" 35.50 36'35" 25"
37.45 30'30“ 20" 35.55 36'45" 10"
37.40 30'50" 20" 35.60 37'15" 30"
37.35 31'10" 15“ 35.65 37'40" 25"
37.30 31'25" 20“ 35.70 38'00" 20"
37.25 31'45“ 20" 35.75 38'25" 25"
37.20 32'5" 15" 35.80 39'10" 45"
37.15 32'20" 20" 35.85 39'25" 15"
37.10 32'40" 20" 35.90 40'00" 35"
37.05 33'00" 15" 35.95 40'30" 30'
37.00 33'15" 15" 36.00 41'20" 50"
36.95 33'30" 30" 36.05 44'10" 2'50"
36.90 34'00" 15" 36.10 46'15" 2'5“
36.85 34'15" 15" 36.15 47'35" 1'20"
36.80 34'30" 25" 36.20 48'45" 1'10"
36.75 34'55" 25" 36.25 50'30" 1'45"
36.70 35'20" 5" 36.30 52'40" 2'10"
36.65 35'55" 17'40" 36.35 55'15" 2'35"
36.60 53'35" 2'0" 36.40 57'30" 2'15"
36.55 55 '35" 1'30" 36.45 61'0" 2'30"
36.50 57'5" 1'0" 36.50 62'15" 1'15"
36.45 58'5" 1'10" 36.55 64'45" 2'30"
36.40 59'15" 50" 36.60 65'15“ 30"
36.35 60'5“ 30" 36.65 75:15" 10'0"
36.30 60'35" 30" 36.70 76'0" 1'45"
36.25 61'5“ 30" 36.75 77'15" 25"
36.20 61'35" 25" 36.80 77'40“ 25"
36.15 62'0" 25" _ 36.85 78'5" 25"
36.10 62'25" 20" 36.90 78'30" 25"
36.05 62'45" 15" 36.95 78'55" 25“
36.00 63'0" 15" 37.00 79'20" 20"
35.95 63'15" 15" 37.05 79'40" 25"
35.90 63'30" 15" 37.10 80‘5" 20"
35.85 63'45" 15" 37.15 80'25“ 20"
35.80 64'0" 20" 37.20 80'45" 15"
35.75 64'20" 15" 37.25 81'0" 20"
35.70 64'35" 15" 37.30 81'20" 15”
35.65 64'50" 15" 37.35 81'35" 20"
35.60 65'5"- 10" 37.40 81'55” 20"
35.55 65'15" 10" 37.45 82'15" 20"
35.50 65'25“ 10" 37.50 82'35" 20"
35.45 65'35" 37.55 82'55"

22

PROCEDURE

 

The alloys used were made up on a weight percentage
basis as shown in Table 2. The metals were placed in the
crucible as shown in Fig.6. The crucible was covered with
an alundum cover, placed in the Ni-Chrome wire carrier and
the furnace sealed. After the metals had melted, the thermo-
couple was inserted, and the furnace resealed. The metal
mixture was superheated to lSOOOF. to assure as much diff-
usion as possible. A cooling curve was then run on the alloy,
inserting a constant external resistance into the furnace
circuit to cause the dr0p of any small increment of temp-
erature to take place over a reasonably long period of time.
After the cooling curve, a heating curve was run to determine
the amount of hysteresis. The thermocouple was then with-
drawn and the alloy allowed to cool in air.

A heating and cooling curve were run on all alloys.
However, since there was such little hysteresis and no
startling revelations other than that they paralleled one
another and the cooling curve had fewer unreasonable flu-

ctuations, the heating curves were omitted from the data.

[E
<

37.00
35-95
36.90
36.85
36.80
36.75
36.70
36.65
36.60
36.55
36 050
36 045
36040
36.35
36.30
36025
36020
36.15
36.10
36.05
36.00
35-95
35.90
35.85
35.80
35.75
35.70
35.65
35.60
35.55
35.50
35.45

TABULATED DATA

 

TABLE VI Data

 

Cooling
Time Time a;
Temp.
0'00" 10"
10" 10:
N
:8" i8"
402 15:
l?§0" i2"
11'20" 25"
22'45" 10'30"
27'15N 11'25N
ggzge" 412,22"
34'55N 2'40"
36:15: 11553
as. 1.58..
38'55“ 45"
39'30“ 35"
40'15r 45"
40.35" 20"
41110" 35"
41'50" 40"
42'553 115”
43'25N 30"
43'45" 2o"
44'5" 20"
44'25" 20"
44'45" 20"
4515" 20“
45'20" 15"
45'35" 15"

for the transformation of

 

35.50
35-55
35.60
35.65
35.70
35.75
35.80
35.85
35-90
35-95
36.00
36.05
36.10
36.15
36.20
36.25
36.30
36.35
36.40
36.45
36.50
35-55
36.60
36.65
36.70
36.75
36080
36.85
36 090
36.95
37.00

._ 22%
Esaiiss
Time Time pp
Temp.
9'00" 20"
9'20" 20"
9'40" 20"
10'0" 20"
10'20" 25"
10145" 25"
ll'lO" 25"
11135" 20"
11'55' 25"
12320" 30"
12'50" 40"
13130" 55"
14'25“ 1'10"
15'35" 1I55N
13:39" 5:30;:
2 5
21:15" 1:45:
32:35» 83?
26:45: §:20:
29 35 5
33120" 11.25"
24:23" 3:52"
53145" 5%"
51'35" 55"
52l30" 45“
53315" 45"
54'0" 50"
54'50N 1+0"
55'30"

 

24

 

 

TABLE VII Data for the transformation of .10%
antimony 33 aluminum. (Figure 27— " "‘
Cooling Heating
Mv. Time Time a} EX; Time Time at
TemEo Temp.
37.00 0'00" 20" 35.85 0'00" 1’5"
36.95 2o" 25" 35.90 115" 1'15"
36.90 45" 25" 35.95 2'20" 1'0"
36.85 1'10" 25" 36.00 3'20" 50"
36.80 1'35" 25" 36.05 4'10" 50"
36.75 2'0" 25" 36.10 5'0" 55"
36.70 2'25" 25" 36.15 5'55” 1'15”
36.65 2'45“ 30" 36.20 7'10" 1'15“
36.60 3'15" 25" 36.25 7'25" 2'30"
36.55 3'40" 25" 36.30 9'55" 2'15”
36.50 4‘5" 25" 36.35 12'10" 3'55"
36.45 4'30" 35“ 36.40 16'5“ 3'50"
36-40 '5" 55" 36.45 19'55" 4'55”
36.35 6'0“ 30'30" 36.50 24'50" 3'5"
36.30 36‘30" 3'45“ 36-55 27'55“ 50"
36.25 40'15“ 1'20" 36.60 28‘45" 25"
36.20 41'35" 1'20" 36.65 29'10" 35“
36.15 43'15" 1'10" 36.70 29'45" 15”
36.10 44'0" 1915“ 36.75 30'0" 15"
36.05 45'15" 35" 36.80 30'15" 35"
36.00 45'50" 30" 36.85 30'50" 35"
35.95 46'20" 35" 36.90 31'25" 35”
35.90 46'55" 25“ 36.95 32'0" 30"
35.85 47'20" 25" 37.00 32'30" 30"
35.80 47'45“ 30" 37.05 33'0"
35.75 48'15" 30"
35.70 48'45"

 

 

 

 

25

 

 

 

TABLE VIII Data
for
antimqpy i2.aluminum.E%%iéiigsigimation Of .20%
Coolin _—

MV. 5 Heating
___ Time Time at M
37 5 Tem.7_ p1; Time Time a

. O I N Te
37.45 2'89 1'0" 35 50 ' m .
37.40 2:10" 1'10“ 35.5 2 7" 15"
37.35 3:0" 50" 35.53 2:22" 20“
37.30 3:35" 35" 35.65 2 42" 18"
37.25 4'30 55" 35.70 2:60“ 22"
37.20 5'25“ 55" 35.75 3.22" 18"
37.15 6'10" 45" 35.80 3,40" 17"
37.10 6'50" 40" 35.85 3 57" 370.
37.05 7.30" 40" 35090 4'30" 40"
37.00 8'30“ 130" 35.9? 5'10" 45"
36.95 9'10» 40" 36°05 5'55" 1.0"
36.90 10:0» 50" 36.0 6.55" l 10"
36.85 10'40" 40" 36.18 8'5" 55"
36.80 11'20" 40" 36.1 9'0" 40"
36.75 12'0" 40" 36 23 9.40" 1.25"
36.70 12v45n 45" 36.2 11.5" 1.25"
36.65 13:5» 20" 36 36 12:30" 1 45"
35.50 13.40" 35“ 36 35 14.15" 2:30»
36.55 14'son 1'10" 36 40 16 45" 45"
36.50 18v1 u 3'20" 36.4 17.30" 2.30"
36 O 10.30" . 5 20'0" ' N

.50 18'10" 36 SO ' 10 30
36.45 28'40N 10'30" 36.50 30 50" 3.20"
36.40 31:10» 2'30" 36 55 30:50" 3.20"
36.35 31:55“ 45" 36.60 24'10" 1.10"
36.30 34,25" 2'30" 36.6 )5 20" 35"
32°25 36'10" 1:25: 36:78 32:82: 20"

.20 t H I 4 u
36.10 39'40u 40" 36 85 37.40" 40"
36.05 40'35N 55“ 36 90 38.20" 40"
36.00 41.45“ 1:10“ 36 95 39'0" 50"
35.95 42.45» 1'0" 37.00 39.50" 40"
35.90 43'3on 45" 37 05 40:30" 1.0"
35.85 44010» 4O" 37 10 41'30" 40"
35.80 44'47» 37“ 37:15 42.10" 40"
35.75 45.04" 17" 37 20 42I50" 45"
35.70 45.22" 18“ 37-25 43,35" 55w
35.65 45.44" 22“ 37030 44.30" 55"
35.60 46'2" 18" 37°35 45'25" 35"
55.55 1...... $01: 372.. $2.23.. 5""
35.50 46.37" 5 37°45 48'0" 1:12"

37.50 49'0" 1 O

 

 

 

26

TABLE IX Data for the transformation of .30%
antimonx_ in aIuminum. (Figure 11)

 

Cooling Heating

M1; Time Time g3 My; Time Time §3_

Temg. Temp.
37.00 0'00" 15" 35.50 1'15" 10"
36.95 15" 20" 35.55 1'25" 10"
36.90 35" 25" 35.60 1'35“ 10"
36.85 1'0“ 30" 35.65 1'45" 15"
32.80 1:30: 25: 35.70, 2:0"" 15:
2.572% 122"?» 22:53 3%? 5%»
32.25 2:0: 1:0: 35.85 2:50: :0:
25:52 7.8» 32 So» 32:32 268» 1.8"
36.50 39'10" 13' 20" 36.00 5'10" 35"
36.45 52'30" 4'0" 36.05 5'45 " 50"
36.40 56'30" 1'30" 36.10 6'35" 1'15"
36.35 58'0" 1'0" 36.15 7'50" 1'10"
36.30 59'0" 40" 36.20 9'0" 1'25"
36.25 59'40" 50“ 36.25 10'25" 1'50"
36.20 60'30" 35" 36.30 12'15" 2'15"
36.15 61'5" 40" 36.35 14'30" 2'55"
36.10 61'45" 40" 36.40 17'25“ 3'20"
36.05 62'25“ 25" 36.45 20'45" 3'35"
36.00‘ 62'50" 25" 36.50 24'20" 2'30"
35.95 63'15“ 1'25" 36.55 26'50" 3'00"
35.90 64'40" 25" 36.60 29'50“ 1'40"
35.85 65'5" 25" 36.65 31'30" 2'00"
2222 22:23:! :3: 222 22:30:: 283

. . 20
35.70 66'25" 30" 36.80 35'0" 25"
32°23 212;- 3811 2233 226‘?" 3811
. 2 .

35 .55 67 I45“ . 20" 36 .95 36 t 50" 30"
35.50 68'5" 37.00 37'20“

 

 

27

 

 

.‘_1‘_____I_._E )5 Date. for the transformation _0__f .3972
antimony _13 aluminum. TFigure L2)
Qooling Heating
fl. Time '_I‘_ig_e_ at My. ' Time Time 33
Temg. TemE.
37.25 0'00“ 30" 35.50 1'20" 10"
37 .20 30" 25 II 35 . 55 l I 30" 30"
37.15 55" 25" 35.60 2'00" 10"
37.10 1‘20" 35" 35.65 2'10" 15"
37.05 1'55" 35" 35.70 2'25" 20"
37.00 2'25" 30" 35.75 2'45" 15"
36.95 2'50" 25" 35.80 3'00" 25"
36.90 3'10" 20" 35.85 3'25" 30"
36.85 3'30" 20" 35.90 3'55" 5"
36.80 4'0" 30" 35.95 4'30" 1'15"
36.75 4'20" 20" 36.00 5'45" 1'35"
35-70 4'55" 35“ 36.05 7'20" 2'10"
36.65 5'15" 20" 36.10 '30" 2'00"
36.60 '40" 3'00" 36.15 11'30" 1'20"
36.55 8'40" 3'00" 36.20 12'50" 1'30"
36.50 11'40" 19'20" 36.25 14'20" 1'45"
36.45 31'00" 4'5" 36.30 16'5" 2'10"
36.40 35'5" 1'50" 36.35 18'15" 2'35"
36.35 36'55" 1'5" 36.40 20'50" 3'10"
36.30 38'00" 40" 36.45 24'00" 3'45"
36.25 38'40“ 50" 36.50 27'45“ 3'15"
36.20 39'30" 30" 36.55 31‘00" 2'00"
36.15 40'00" 30" 36.60 33'00" 1'50"
36.10 40'30" 25" 36.65 34'50" 1'35"
36.05 40'55" 1'00" 36.70 36'25" 1'35"
36.00 41'55" 25" 36.75 38'00" 1'10"
35.95 42'20" 20" 36.80 39'10" 1'15"
35.90 42'40" 20" 36.85 40'25" 1'5"
35.85 43'00" 20" 36.90 41'30" 1'5"
35.80 43'20" 36.95 42'35" 1'10"
37.00 43'45" 45"
37.05 , 44'30" 45"
37.10 45'15" 45"
37.15 46I00fl 45"
37.20 46'45” 35“
37 .25 [+7 I 20" 25"
37.30 47'40" 10"
37.35 47'50"

28

TABLE XI Data for th
__ e transf
antimony in aluminum. (FigureOI53tion 23 .29%

 

 

Cooling Heating

Mv.

___ Time Tim; g__ M1; Time
37 . 50 I II I.

37.45 018% 1%" 35.50 0'00"
37.40 25" 15" 35°55 15"
37.35 40" 15" 35.60 30"
37.30 55" 15" 35.65 40"
37.25 1'10" 20" 35.70 55"
37.20 1'30” 20" 35.75 1.15"
37.15 1'50" 20" 35.80 1.35"
37.10 2'10N 15" 35.85 2'5“
37.05 2'25" 25" 35.90 2.50"
37.00 2'50" 20" 35°95 4'0“
36.95 3'10" 20" 36.00 5.30"
36.90 3.30" 30" 36.05 6'15N
36.85 4'0" 35“ 36.10 6'35"
36.80 4'35" 50" 36°15 7.35"
36.75 5'25" 1.15“ 36.20 9'40"
36.70 6'40" 2'10" 36.25 11.35"
36.65 8'50" 13'25" 36.30 14.5"
36.60 22'15" 14'5" 36'35 16.45"
35.55 36.20" 3'10" 36.40 19'A5“
35.50 39.30" 2'20" 36.45 23.5"
36.45 41'50" 1'45" 36°50 27.55"
36.40 43'35" 1'10" 36°55 36.45"
36.35 44.45" 55" 36.60 44'6"
36.30 45.40" 55" 36.65 46'20"
36.25 46'35" 25" 36°70 47.5“
35.20 47.0" 35“ 36.75 48.00"
36.15 47.35“ 30" 36.80 49'0"
36.10 48'5" 30" 36°85 50 O“
36.05 48'35" 30" 36.90 51.10"
36.00 49'5" 25" 36.95 52'25"
35.95 49'30" 30" 37.00 53.35"
35.90 50.0" 30" 37.05 54'45"
35.85 50'30" 50" 37.10 56.25"
35.80 51.20“ 25" 37.15 57'35"
35.75 51'45" 20" 37.20 59.0"
35.70 52'5" 15" 37.25 60.15"
35.65 52'20" 15“ 37.30 61.0"
35.60 52'35" 15" 37°35 61.30"
35.55 52'50" 15" 3g':5 23:55:

. I II .

35 50 53 5 37.50 62'5"

 

 

 

0-3
(D
B

29

TABLE XII Data for the transformation of .§9%
antimony in aluminum. (Figure 137

 

 

Cooling Heating

M1; Time Time at M1; Time ime a

TemE. Temg.
37.50 0'00" 10" 36.00 0'00" 1'5"
37.45 10" 15" 36.05 1'5" 1’10"
37.40 25" 15" 36.10 2'15" 2'5"
37.35 40" 20" 36.15 4'20" 2'40"
37.30 1’0" 20" 36.20 7'0" 1'45“
37.25 1'20" 25" 36.25 8'45" 2'0"
37.20 1'45" 25" 36.30 10'45" 1'30"
37.15 2'10" 20“ 36.35 12'15“ 2'0"
37.10 2'30" 25" 36.40 14'15" '15"
37.05 2'55" 30" 36.45 17'30" 3'10"
37.00 3'25" 25" 36.50 20'40" 5'15"
36.95 3'50" 20" 36.55 25'55" '55"
36.90 4'10" 35“ 36.60 31'50" 6'40"
36.85 4'45" 25" 36.65 38'30" 2'40“
36.80 5'10" 35" 36.70 41'10" 1'25“
36.75 5'45" 35" 36.75 42'35" 1'40"
36.70 6'20" 3’30" 36.80 44'15“ 1'15"
36.65 9'50" 16'55" 36.85 45'30" 1'0"
36.60 26'45" 10'25" 36.90 46'30" 1’20"
36.55 37'10“ 4'0" 36.95 47'50" 1'0"
36.50 41'10" '0" 37.00 48'50" 1'15“
36.45 44'10" 2'10" 37.05 20'5“ 1'5"
36.40 46'20" 2'0" 37.10 21'10" 1'5"
36.35 48'20" 1'5" 37.15 21'45" 35"
36.30 49'25" 50" 37.20 22'0" 15"
36.25 50'15" 45" 37.25 22'10“ 10"
36.20 51'0" 40" 37.30 22'20" 10"
36.15 51'40" 35" 37.35 22'30“ 10"
36.10 52'15" 35" 37.40 22'40" 10"
36.05 52'50" 30“ 37.45 22'50“ 15"
36.00 53'20" 40“ 37.50 23'5"
35.95 54'0” 45"
35.90 54'45" 35"
35.85 55'20" 25”
35.80 55'45" 30“
35.75 56'15" 25"
35.70 56'40' 20“
35.65 57'00" 15"
35.60 57'15" 15"
35-55 57'30" 15"
35.50 57'45"

 

 

 

30

TABLE XIII D
ata for th
antimony in aluminum_—T%it::25£g§mation Of .70%

 

 

Cooling
M . Heating
_L Time Timeég REV.
Temp. ' “‘“ 2393 ligg at
37050 4'25" 2392-:-
37.45 4'40" 15” 35.50 0' u
5-22 i2: 25-25 139 i8:
0 5'25" ' 50 O N
37.30 5035“ %8; 35.65 58" 10:
37.25 6'5" 15" 35070 55“ 25"
gg°fg 2:20" 20" 33'65 1'40“ 1??"
e 40" 0 O ' “
g;.%g 5'55" :3: 35.85 i'25“ 4:55:
. 7I15" 090 I"
. 7 55" “ .00 12' n
36.90 8'20" 25 36.05 '55 3'25"
36.85 8' n 20“ 36.10 15'20“ 4.55”
.29 5:: 2:2:
56.75 9'40" 30“ 36.20 26'00n 2 32"
30.70 10'10" 10“ 36‘25 26'25“ 25"
36.65 10:20. ” 36.30 33.40" 25
. 11'15" " 3 .40 45.10"
56.50 11040" 15 36.45 4 I n 40"
36.45 12'1on 30" 36 50 45'50 1'10"
' . O N
32-22 12:20: 1583 222a 4903" 5‘93"
e 10 _ I . 49.30"
36.30 23'0" 7 50" 35°65 ' " 45”
35.25 42'5" 19.5" 36-70 50‘15" 1.15“
36.20 46'35" 4:30“ 36 75 51.30 1'0“
0 2 II
3243 .22.. 32-20 23:
' 52'15" ' u ’ 5 53'2 "
36.05 53.45" 1 30 36.90 ' 5" 25'!
36.00 54.55" 1'10" 36.95 52.50" 10!
35.95 56'5" 1'10" 37-00 54'00" 10"
35.90 55*50" :3: 37-05 54'28" 10:
2223 5-10 18"
. 0" .15 4' a
22.78 58'30" 58: £7.20 24'28" I8:
- 59'0" u ~25 55'00"
35.65 59.20. 20 37.56 . .. 10"
35060 59.45" 25" 37035 55'10" 15”
35.55 60'20" 35" 37.40 55'25n 10”
35.50 61135" 1'15" 37.45 22.23" 15:
37.50 55'00" 10

 

 

 

31

Coolin
EX; Time 5 Heating
Time at NV
Temgt‘ i_; Tim 2
37.50 8'1 " e Iigg EL
37.45 8' 5" 20" Tern .
37.40 9%? 30" 35.50 0'00" "
37.35 9.2 fi 20" 35.55 25" 25
37.30 '9' g" 25” 35.60 n 30"
37.25 10.; u 25" 35.65 1'20" 25"
37.20 10.43" 25“ 35070 1'50" 30"
37 .15 11.5" ~ 25" 35075 2' 20" 30"
37.10 11.30” 25" 35.80 2'50" 30"
37.05 11'55n 25" 35’85 3'25" 35"
37.00 12.20» 25" 55°90 4'10" $5"
36.95 12'50" 30" 35095 5'10" 1'00"
36.90 13:1 u 25" 36.00 6'30" 1'10"
36.85 13:48» 25" 36'°5 7'50" 1 20"
35.80 14'10" 30" 36.10 10'20" 2:30"
36.75 14'40n 30" 36.15 12.20“ 2.00"
36070 15.20" 40" 36020 14.10" 1 50"
36.65 16i1 n H 36.25 16'5" 1.55"
36060 g 5. 1'45" 36.30 18' a 2.10"
6 18 OO' 36 15 2' I
3 .55 20.5". 2P5" .35 20'45n .30
36.50 36.4 " 16.40" 36.40 24'15" 3 30"
36.45 47'45" 11100" 36.45 29.00" 4.45"
36.40 51.23" 3'35" 36050 35.50" 6:50"
36.35 53.20" 2.00" 36.55 42'25n 5,35»
36.30 54'4 n 1’25" 35-50 44'30" 2 5"
3.6 025 55 ' 45" 1'00" 36 065 45 ' 20" 50"
36.20 56:38" 45" 36-70 46'45" 1.25"
36.15 57'1 u 40" 36.75 48.5" 1.20"
36.10 57:48" 30" 36‘80 49'25" 1.20"
36.05 58'1 n 35" 36°85 50.25" 1.00"
36.00 58.43" 25. 35°90 51'35" 1.10"
35.95 '5" 25" 35095 52'50" 1:15"
35.90 59'30» 25" 37°00 54.00" 1.10"
35.85 59.5 n 25" 37.05 55'15" 1,15"
35.80 6o'égu 30» 37°10 56.25" 1'10"
gg.;g 61.40" 111?" §;.ég 57'45" 135g:
. 61'50" O. 3 o 59.00" 1' "
35.65 ' N 25" 7.25 60' n 10
35.60 gg'ég" 15" 37.30 60'égn 10:
35.55 62.4 n 15" 37035 60.30” 10"
35.50 63' 5" 15» 37.40 60'40u 10
00 37.45 60'55” 15"
37.50 51'5" 10"

 

32

TABLE XV Data for the transformation of .90%
antimonx in aIuminum. (Figure 177

 

Cooling Heating
M2; Time Time 4.1». 42:. 2mg
Temg.

37.50 6'5" 25" 35.50 0'00"
37.45 6'30" 25" 35.55 10”

37.40 6'55" 20" 35.60 30"

37.35 7'15" 25" 35.65 55"

37.30 7'40" 25" 35.70 1'30"
37.25 8'5" 25" 35.75 3'5"

37.20 8'30“ 25" 35.80 4'50"
37.15 8'55" 25" 35.85 6'30"
37.10 9'20" 25” 35.90 7'55"
37.05 9'45" 25" 35.95 9'25"
37.00 10'10" 25" 36.00 11'00"
36.95 10'35" 30" 36.05 13'5"

36.90 11'5" 25" 36.10 16'35“
36.85 11'30“ 25“ 36.15 21'20"
36.80 11'55" 25” 36.20 28'00"
36.75 12'20" 25" 36.25 33'25"
36.70 12'45" 25" 36.30 37'25"
36.65 13'10" 25" 36.35 38'30"
36.60 13'35" 25" 36.40 39'30"
36.55 14'0" 25" 36.45 40'00"
36.50 14'25“ 30" 36.50 40'50"
36.45 14'50" 45" 36.55 41'40"
36.40 15'40" 1'50" 36.60 42'30"
36.35 17'30” '50" 36.65 43'25“
36.30 20'20" 2'30" 36.70 44'5"

36.25 33'10" '55” 36.75 45'00"
36.20 41'50" 8'40" 36.80 45'35“
36.15 *46'35" 4'45" 36.85 45'50'
36.10 49'50“ 3'15" 36.90 46'5"

36.05 52'30" 2'40" 36.95 46'20"
36.00 54'40“ 2'10” 37.00 46'35"
35.95 57'0" 2'20“ 37.05 46'55'
35.90 59'15“ 2'15” 37.10 47'05"
35.85 61'25“ 2'10" 37.15 47'15"
35.80 63'5" 1'40" 37.20 47'25"
35.75 64'15" 1'10" 37.25 47'30"
35.70 65'5“ 50" 37.30 47140"
35.65 65'50" 45" 37.35 47'50"
35.60 66'25“ 35' 37.40 48'00"
35.55 67'0" 35” 37.45 48'15"
35.50 67'35' 37.50 48'25"

 

 

 

 

33

TABLE XVI Dgt
a for the t
EEE£2221.$2 aluminum. (F123;:f$§?at1°n 92 1.00%

Cooling
Heatin
Ml; Time Time a M —————.E
TemR. ‘24 IlEE Time at

37.50 3'00" " 2292
37.45 3'20" 20“ 55.50 ' n
2;.13“; 3 ”+0" 38" 55 '25 0189 :8:

. 4'00" n . O u
37.30 4.20" 33" 35.65 &§g" 15:
37.25 4'40" 15" 35070 '50" 15"
gg'ig 4'55" 20" EE'ES 1'10" $2"

. 5'1 :0 u . O c n J

' 5'55" 2 u '90 2'20"
37.00 6'1 N O" 35.95 ! u 40"
2233 3'22» .52..

. 6! 0" n .05 I u
36'85 7'§5" :8" 36-10 2'62" 1:15:
32‘32 7'35" 30" 32°15 7'40" i'58"

. 8' t. " .20 c u '
36.70 8'20" :2" 35,25 lg'ég" 1.42"
36065 9'45" 55" 56.30 13100" 2'5"
36'60 10'40" 1'20" 35°35 16'00" 3:0 u
36.55 12'00" 2'20» 35-40 19'40" 3:40"
36.50 14'20" 16'1 N 36.45 25'00u 2,20"
36045 30.35" 3'25" 36050 31100" '02
36.40 34'00u 3,25" 36.55 3415" 3.5 u
35-35 37'25" 2'02 35°50 35'20" l I?
36.30 39'25" 1'30" §6o65 36315" 55“
36.25 40155" 1.5" 56.70 37'10" 55"
36.20 42'00" 5 " 36.75 8'0" ?0 n
36.15 42'55" 32" 36.80 39'10" l 19
36.10 43 '30" 30" 36.85 59.55" 45"
36.05 44'00" 25" 36.90 40'45n 20“
36 .00 44 ' 25" 20" 36 .95 41'30" 5"
35095 44'45" 20" 37.00 42'25u 55"
35'90 45'5" 20" 37‘05 43'20" 55"
35°85 45'25" 15" 37'10 44'00" 40"
35-80 45'40" 15" 37.15 44'50" 50"
35075 45'55" l u 37.20 45135" 45"
35-70 45'10" 15" 37.25 45'25n 50"
35065 46'25N 15" 37.30 47'15" 50"
35.60 46'40u 20" 37.55 4815" 50“
35.55 47:00" 20“ 37.40 48'55u 50"
35-50 47'20" 37°45 49'35" 20"

37.50 50'20" 5

 

 

 

34

TABLE XVIII Data for the tra.nsformation of 1.10%
an nEIm monz In aIu minum. {Figure“I9T

 

 

 

 

 

Cooling Heating
Mv. Time Time at Mv. Time Time g3
Temg. Tg_2.
36.65 0'00" 10“ 35.50
36.60 10" 30" 35.55 0'00" 1'10"
36.55 40” 1'20" 35.60 1'10" 1'5“
36.50 2'09 3'30" 35.65 2'15" 1'0"
36.45 5'30" 3'55" 35.70 3'15" 1'5"
36.40 9'25" 3'15" 35.75 4'20“ 1'5"
36.35 12'40" 3'10" 35.80 5'25" 1'15“
36.30 15'50" 2'15" 35.85 6'40" 1'10"
36.25 18'5" 3'10" 35.90 7'50" 1'25"
36.20 21'15“ 2'45" 35.95 9'15" 1'20“
36.15 24'0" 2'45" 36.00 10'35" 1'45"
36.10 26'45" 2'35" 36.05 12'20" 1'50"
36.05 29'20" 2'5" 36.10 14'10“ 2'10“
36.00 31'25" 1'25" 36.15 16'20" 2'20"
35.95 32'50" 1'0“ 36.20 18'40" 3'30"
35.90 33‘50" 55" 36.25 22'10“ 3'25"
35.85 34'45" 55" 36.30 25'35" 5'20"
35.80 35'40" 50“ 36.35 30'55" 3'20"
35.75 36'30“ 40" 36.40 34'15“ 3'55"
35.70 37'10" 35" 36.45 38'10" 2'25"
35.65 37'45" 30" 36.50 40'35" 1'25"
35.60 38'15" 40" 36.55 42'0" 1'5"
35.55 38'55" 25" 36.60 43'5“ 1'0"
35.50 39'20" 36.65 4A'5" 40"
36.70 44'50" 35"
36.75 45'25" "
36.80 46'00" 25"
36.85 46' 25“ 10"
36.90 46' 35" 10"
36.95 46' 45" 10"
37.00 46' 55"

Db

 

50

 

 

 

 

4L

 

 

 

 

 

 

47

DISCUSSION

From the flat portions of the preceeding curves,
which indicates the beginningof solidification upon
cooling, it appears that the liquidus falls to a min-
imum at .3% antimony, from which the liquidus rises to
a Iaximum at .6% antimony and then drops to another min-
imum at .9% antimony and then rises once more. This would
tend te show the formation of eutectics at .3% and .9%
antimony and the formation of an intermetallie com—
pound at .6% antimony.

The solidus curve, shown by the very slight
break in the cooling curves at approximately 12000F.,
shows considerable fluctuation which is notoriously
true of most attempts to show a solidus by thermal
measurements.

It was found that to assure good diffusion of
the antimony, the melt had to be superheated. This
difficulty was also experienced by Dix, Keller, and
Willey.

Further discussion of the cooling curves will
be made at the end of the section where an attempt will
be made to correlate these curves with the micro-

structure.

48

31;. THE MICROSTRUCTURE 95 THE ALLOYS

 

 

GENERAL THEORY

According to Dix, Keller and Willey7 the solid
solubility of antimony in aluminum appears to be less
than 0.10 per cent. Microscopic examination of this alloy
showed particles of Ale constituent out of solution.

These authors found that upon additions of higher
percents of antimony, it was found that the eutectic con-
centration was approximately 1.1 per cent antimony. Although,
at concentrations which should produce a eutectic both pri-
mary aluminum and primary Ale occurred in the same field.

Since the metals used in this experiment were not

pure, the microstructures were expected to be somewhat

complex.

 

49'

PROCEDURE

Samples were out from the bottom portion of the
air eooled ingots used for the cooling curves. These
were filed flat, ground on a belt grinder, and polished
successively on #1 paper, #0 paper, 320 wet wheel, 520
wet wheel and levigatcd alumina wet wheel. All finish
polishing was done with re-levigated alumina on bill;
lard sloth. A magnesia paste on a silk wheel was at-5
tempted but apparently the base wheel was of the wrong
composition since the samples became badly corroded.

The samples were etched in a 10 percent EaCH
solution at 160°F. for 5 seconds and then examined

before being photographed.

50

MICROSTRUCTURE Q§_THE ALLOYS

" PHOTO #1 - Showing
microstructure of alum-
inum- 0% antimony.

"Li, .. ’ ‘_j,.. Fe2A17 present at upper

I»..5~{_ l’.”lf..“”’ right, FeSiA15 at grain

3»‘;'§jld'mf-*,‘g _' boundary with eutectic

"'m*-&gfi:gyj 314'”; Al-Si. 250x

 

structure of .05%
antimony alloy
showing apparent ‘
incre‘se in boundary * .1 :~,» ”a .;~
eutectic. 250x 7 {,‘_.: T_ 3.?\”

"PHOTO #2 - micro- . _ l
: " '

 

 

.- . .;r '7... 5,,» . 3'7
. “£331? ffq§mdj PHOTO #3 - micro-
" "ngF;74fl*fi structure of .1% anti-
. . :-f:=.i..: mony alloy shows
":"fff~fi§?*-;« apparent disappearance

' i" 155"; .
,"$t..gzy.4 of majority of boundary
a T; '9;Ys7 constituents. 250x
may: 59' J" i "y" "$4.2 3’3:
V ‘5. :quéh.’ ‘:1 "7.1.1.". “‘5'
-..»..~wwxr~
1:}:‘3'.’ 5. “V. 1:3
";,.‘.'_.‘1' ’ ‘ ‘ "
5:541; ) ';§2“.~g~;?r);2"
‘3'.“ 4‘ * .'_'-“.-,‘ .'
' 'yfie. .- .x j?“ .

 

 

   
     

       

I . '
q" .' .. . --I'-'>'.'.-
. ”\ . ‘ .'« ~\ - ‘» .
. e 'fl 3» ' t
"" x - 7' '. '4 .
. h x ' ‘ss' ' ‘ fl , .
e. ( ~ ‘ .' A ' ' .
. ' '. _ I ' .' : I 7.
“ .I . . "3 ‘ ‘ ‘ . .v' e. ' ‘ .~ . ‘,
. 2'» n$.;ss : a.
-‘ ' g . V' ‘ ' I ‘; ~ s
.‘v i ‘ ' u ‘ . ’ ~ ‘
I . l. x.- ,. ,tn , ; .-- -.
. l .‘ ‘ 50...} I'li‘ Heir ‘ ' . ..‘
f e " a— 3: T w \ H”
“L‘- g ,.'- . V VI‘ - I: ' . '

PHOTO #5 - Micro-
structure of alloy
containing .3%
antimony. 250x

 

 

. ' ‘ .
\ 5 '
l . K 4 ‘ "
s ' ’ i. L ‘ ‘ , s
e . .0 " . . '
a, r s . ',\ - . .' A .
¢ " C ,’ ’ - .
, . .
e 1 . ' '

PHOTO #4 - Micro-.
structure of alloy
containing .2% anti-
mony. Two phases present
but little eutectic.
Predominantly impurity
phases. 250x

_- 3, . . 'e,
\ 9‘ 1d. 1
c- -
? §
" I .

PHOTO #6 - Same as 5.
Showing appearance of
different phase (dark
gray) lower left of
photo. 500x

 

 

'. ' .‘ 3'; ,4»

. -.~ ‘

as . x
4" .e‘.‘

PHOTO #8. Same as 7.
Showing gray constituent
in long angular form at

lower right. SOOX

f e \‘FN _- ~~ fr'1"-
» , , '. new“. -'
I‘. ' ' III“ .I.
Q I IA -.~. ' v“- L
. w - ”he 7
ll , ' ’
I o

52

PHOTO #7 - Micro-
structure of the alloy
containing .4% anti-

mony.

b

. ’ ’1‘:

. ‘- _
l . i
‘\ --
a
. -.
. l
‘
,. o
"D
. L ‘
‘ f
s “
z .
. “ ...

Q
14’

250x

.L‘c
‘3

19'

' 7
;~ .,
‘ ‘ I‘

a ‘ . ,

e ‘ V

\ ' ,
L ' $ 'A '
A ' .
.

«a. fl
)3

PHOTO #9 - Micro-
structure of the alloy
containing .5% anti-

mony.
present.

Little eutectic
250x

53

PHOTO #10. Same as 9.
Showing angular shapes
of gray constituent, no
eutectic. Appearance of
black constituent in
lower center. 500x

 

 

‘ ...:};1. q. ‘."_‘ 51-”, r .' in 5:""—:.‘I. u i
. wai‘fif‘ :,-,§.j;..~¢,&pr y‘gjwpi ..

     

PHOTO #11 - Micro- . 1.94-7..3-‘35 31:1{flailigééfi’ffi2;
structure of the alloy i_t§&§§quii“‘“ L'fvfi
containing .6% anti- ' " “ u

mony. Grain boundary
constituents appear all.
bla¢k. 250x

 

PHOTO #12. Same as 11.
Showing a complex shape
of black constituent. A
particle of the gray
constituent present in
lower center» 500x

 

 

PHOTO #13 - Micro-
structure pf the alloy
containing .7% anti-
mony. Showing appearance
of a small amount of
eutectic. 250x

 

 

 

PHOTO #14 - Same as
13. Eutectic contain-
ing black constit-
uent. Gray constituent
still present. 500x

 

 

PHOTO #15 - Micro-
structure of the alloy
containing .8% anti-
mony. Predominantly
eutectic. 250x

 

 

PHOTO #17 - Micro-
structure of alloy
containing .9% anti-
mony. 250x

 

 

55

PHOTO #16 - Same as 15.
Showing the eutectic.
Appears to be slightly
spherical and finely
divided. Majority
formed in grain boun-
daries. 500x

 

u. o. ._ . - . '.\~ 5.)
d‘ - r «‘2: t: -'-' , ’7 ‘ ' 1.1" ’ u‘xirw.
_ . _ I I; _. '._. n\' -. . _. . '_ ‘
. .-l‘ ..~- . 1 .OW'-
I. V _ , ’g‘J" ' 'I l 1‘ '- ‘.") I y . ‘ 7' .‘ c‘x‘
'_ U. .3: .','v ‘.‘ g. . .. V"
‘ - ‘ " ._ ‘4 ' , ' t u '1 ‘ . " a ‘
{.6 fig; ,' .‘ .y . ‘ 1’ .~ .- I t "- “Thu;
\1 I. “N; [R ' a 'O- " I l .' ‘ ". -".~
I I S-" a ‘ ‘. tn 1‘ ‘ If - I. ' ”I ‘ ‘e' ‘t‘i‘
‘ ‘ - _ . rs ‘4 .3 “xi. '.J‘~~. ' ’ 1. “h. F‘ I)
.~3-’,".'_:» ‘ g . ' -\ F .; j‘,"~;< y
|‘ )." ’ .\ I! ‘. . . .) ‘ ..‘\v'1l‘~¢
I ‘ , ' .- . . .
. I ‘ .5 t 'y _ .' h .3 i - fl". 1‘ I.
~.€"' ~ " 4.". Ja‘ I. -'.‘l
I: . .'_ "‘ _ :1. ', 7." .2,I " f ‘.
. , .‘ ‘.’ . ‘\~ ."-: hf \ ‘r. “.t.2. I
I ‘ . 3‘ \ x' - . ‘r -. . i '; A ‘I ’. ‘
.‘e '. *- . ‘ . ‘*V‘ \ " ’ '\
'. _ .- M .‘W‘v- -. . . ‘-‘
‘ ‘ 4 I ’ "s. 3‘ . \ ‘ 'o". "
s . a «g | a» ‘
v . .~ ’- ' “ . . I. ‘ JR". w
-_ a I? . ' . - ‘,/‘ ~d
. .e‘l : \ x ._ 'n
I . ‘ o \. ‘f at.
e ' (4 ’ '
‘ \ V t. g '
I
s A '

PHOTO #18 - Same as

17. Entirely dark

constituent almost com-

pletely surrounding

grain. No light gray

particles apparent.
500x

56

i X / /'
! I I L (I '
| ‘ ‘
. \. ' '

l ’ fl 1’ 1. / ‘ '
‘ 513‘ a. ‘ . igt“: .
‘ F. ‘ ..{’:"’ 9. ’ ‘ . ' ‘. ‘ - a
‘ . I. ‘ae V at: ‘2 I ' I

, - _.. . -/ , g /. . /

PHOTO #20 - Same as 19.
Showing long stringer-
like appearance of a
different light gray
constituent and large
massive black constit-
uent. SOOX

 

 

PHOTO #19 - Micro-
structure of alloy
containing 1.0% anti—
mony. Little eutectic
present. 250x

 

PHOTO #21 - Micro-
structure of alloy con-
taining 1.1% antimony.
Shows little black con-
stituent. Light gray
constituent becoming
more agglomerated. Not
confined to grain
boundary. 250x

57

 

PHOTO #22 - nicro-
structure of alloy
containing .9%
antimony. Showing

hard spherical
constituent of matrix
which has not been
identified. Also

shows black constituent
probably Ale. 2000X

58

DISCUSSION
7
Dix, Keller and Willey found that a chill-cast

 

alloy containing .1% antimony showed very small particles
of Ale constituent in the microstructure, and after var-
ious solution heat treatments, the alloy still showed
particles of Ale constituent out of solution.

The microstructure of the .l% antimony alloy
which was air cooled for this investigation showed the
boundary constituents largely in solution. Whereas the
sample containing .05% antimony showed more grain boun-
dary eutectic and constituents than the alloy containing
no antimony.

Dix, Keller and Willey7 found that the examination
of an alloy containing 1.04% antimony that had been cooled
slowly through the freezing range in a hot graphite mold,.
showed the alloy to be hypoeutectic. Although the alloy
did not show a true eutectic structure, a similiar alloy
of slightly higher concentration, 1.14% antimony showed
a few particles of primary constituent, probably Ale.
They stated that it was apparently impossible to produce
a uniform eutectic structure, since both primary alum-
inum and primary aluminum—antimony compound occurred in
the same field.

However, the alloy containing .8% antimony used
for this investigation shows a eutectic containing the
black constituent which was probably Ale. Undoubtedly,

the slower cooling rate through the solidification

59

of this alloy aided in producing the eutectic. Dix, Keller,
and Willey used a cooling rate approximately 60 per minute,
whereas, for this investigation the melt containing .8%
antimony was furnace cooled at a rate such that the trans-
formation from liquid to solid took place in 17 minutes.
Of course, the rate of cooling in a graphite mold could
hardly be approximated with the facts which are known.

At .1% and 1.1% antimony, another constituent
appears which had not been in the alloys of lower concen—
tration. Also at 1.1% antimony, the black constituent
begins to disappear.

Difficulty was eXperienced in assuring solution
of the antimony upon melting. This difficulty was also
experienced by others working with this alloy. Super—
heating to 15000 F. appeared to overcome this hazard.
However, lower temperatures might possibly be used to

obtain comparable results.

It is possible that the reactions shown to appear
at .3%, .6% and .9% are the result of reactions of
antimony with the impurities and aluminum rather than
the antimony itself. Consequently, no effort was made to

identify the constituents which appeared.

60

II. CHEfi CAL ANALYSIS

 

INTRODUCTION

 

It was thought, since antimony has a low vapor
pressure, that some of the antimony might have been lost
despite the precautions taken in melting.

Therefore, to determine whether there was any
mechanical loss, spot analyses were run on two of the
lower percentage alloys, one medium precentage alloy
and one higher percentage alloy.

Since the impurities included iron, silicon,
copper, magnesium, zinc, nickel and manganese, the hydro—
gen sulfide precipitation method was chosen8.

Antimony sulfide is soluble in a NaOH-Nags
mixture, whereas copper is not and this method of sep-
aration was used. All the other elements are separated

8
by hydrogen sulfide precipitation from an acid solution .

61

PROCEDURE

 

Drillings were taken from test ingots con-
taining .05%, .l%, .5%, and 1.1% antimony. The test
ingots referred to were those used in running the cool-
ing curves for the equilibrium diagram investigation.
The sample was drilled from the cross section of the
ingot exclusive of 1/8" on each side.

The method of analysis was as follows: A 2 gram
sample of the alloy was attacked with 40 ml. of hydro-
chloric-nitric acid mixture, diluted to 150 ml. and
concentrated until pasty to remove oxides of nitrogen
and excess acid.

Since copper interferred with the method used,
the copper was then removeda. The acid mixture was
treated with 3 to 5 grams of tartaric acid, then poured
into the following mixture: 150 ml. of a mix of 60 grams
of sodium sulfide with 40 grams of sodium hydroxide dis-
solved in 1000 m1., diluted to 300 ml. The mixture was
warmed and the insoluble sulfides (copper and lead)
allowed to settle out. Then the solution was filtered
free of the precipitate and the latter washed.

The solution was then acidified with hydrochloric
acid and a rapid current of hydrogen sulfide passed into
the solution for 20 to 25 minutes. The solution was
warned and filtered on No. 541 Whatman paper, washing
with acidified H23 water.

The residue was extracted with hydrochloric

62

acid containing a little potassium chlorate. The solution
was heated to boiling and .5 gram of potassium chlorate
was added. The solution was boiled until colorless and
another .5 gram of potassium chlorate added and the sol-
ution again boiled to very low bulk to remove excess
chlorine and its oxides. The solution was diluted to

50 m1. and evaporated to low bulk once again.

Then 20 ml. of hydrochloric acid was added and
the solution transferred to a 500 m1. conical flask and
diluted to 200 ml. The solution was then cooled to
room temperature and 4 grams of potassium iodide was
added and the solution titrated with sodium thiosulfate
solution, using fresh starch solution as indicatedg.

The sodium thiosulfate solution was standardized
against electrolytic copper. One gram of copper 5 .9576

grams of antimony.

 

63

TABULATED DATA

TABLE XXI RESULTS 9! CHEMICAL ANALYSIS

 

 

%Antimony ZAntimony
Added by by Analysis
weight
.05 .051
.10 .102
.50 .511

1.10 1.122

DISCUSSION

 

From the results obtained, antimony appears to be
of slightly higher concentration than the amounts added
to make up the heat. This amount, however, is approx-
imately only 2%.

This loss of aluminum was probably due to the
oxides of aluminum which were slagged off.

These results would tend to show that the loss
of antimony was nil.

An attempt was made tO‘separate copper by the
use of cupferron. However, it was found to be very
difficult to remove from the filtrate after filtering
the copper salt out of the solution. Also, it was found
that results seemed to be low. This was probably due to
the fact that some of the antimony was occluded upon the

surface of the copper salt.

65

VIII. PROPOSED EQUILIBRIUM DIAGRAM
From the small error in composition shown by the
chemical analysis, no correction was made to the diagram
' resulting from the cooling curves.

7
Dix, Keller and Willey showed in their results

that antimony was soluble in aluminum up to 0.1%. They
also showed that a eutectic was formed at 1.1% antimony
with a eutectic temperature at 657°C as shown in Figure
20. The aluminum and antimony used for their investigation
was very pure and the aluminum had less than .03% impur-
ities.
The diagram produced by this investigation (Figure
21) shows a minimum in the curve at .3% and .9% antimony
with a maximum at .6% antimony. No attempt was made to
show a definite solidus since any attempt to show the
solidus curve by thermal measurements is notoriously in-
accurate. The impurities of the aluminum used in this
investigation were less pure than that used by Dix, Keller,
and Willey. The impurities in the ingot used amounted to
.292%. It is believed that the impurities had a definite
effect upon the sha pe and form of the equilibrium diagram.
The eutectic was shifted to the left and the eutectic
temperature was apparently lowered. There also was the form-
ation of an intermetallic compound apparent at .6-.7% anti—

mony. This was also evidenced by a greater tendency to

cause piping upon cooling from the molten condition.

66

The sample containing .9% antimony was studied by
microscope in an effort to determine whether the hard
particle showing in the matrix of Photo #22 was caused
by any technique in polishing. The sample was originally
polished with alumina. The sample was repolished using
magnesia, etched with 10% NaOH and the particles were
still found to be present at 500x. The same sample was then
repolished with Adolphe Beuhler #1563, chrome green
compound, washed with soap and water, etched with 10%
NaOH, swabbed with hot water and dryed with C.P. ethel
alcohol. The constituent was still present at 500x and
at 2500K. However, the c onstituent was not identified.

The low points in the curve, found at .l% and
.7% antimony were disregarded, since neither was borne

out by the microstructure.

67

‘lllplll.
. .1 ’
til
I
V I
I'll!

 

 

TABLE XIX EQUILIBRIUM DIAGRAM DATA **

 

 

% Sb Li uidus Solidus **

By Weight in.5 (Mv.$
0 56.65

.05 56.60 55.95
.10 56.50 56.10
.20 36.50 36.00
.40 36.50 56.05
.50 56.60 55.90
.60 36.65 35.95
.70 36.30 35.55
.80 56.50 55.80
.90 56.25 56.00
1.00 56.40 55.65
1.10 56.48 55.85
* This data was obtained from the cooling curves

shown in Section I Part I.

** These figures are only approximate since the
change in the slope of the curve was very slight. This
section of the data was included to show the tendency

of the curve to slope downward from 0% antimony.

7O

_I__x. fl EXAMINATION 95 THE PHYSICAL PROPERTIES

 

 

INTRODUCTION

 

Annealed aluminum sheet of high purity has a
tensile strength cf 8,500 p.s.i. with an elongation of
60 per cent in 2 inches and exhibits a hardness of 16
Brinell. Of course, aluminum of purity such as was used
in this investigation, and in the “as cast" condition,
probably would have less strength and less elongation.

This investigation was not for the purpose of
showing the effects of antimony upon all the physical
properties of aluminum, but merely, to indicate the
tendencies of any of the major properties to show a change.
The prOperties investigated include tensile strength,

elongation, reduction of area, and hardness.

71

MATERIALS AND APPARATUS

 

The melting was done in a Hoskins Electric
Furnace of Type FHIO4 with a capacity of 15 volts and
125 amperes. The furnace was connected to a Kuhlman
Transformer, 2K.W., 60 cycle, with a 110-120 volt prim-
ary and 17 volt secondary and to a variable resistance.
(Figure 25)

Slugs were cut from aluminum ingot #5 (Table I)
for the melt and the antimony was of the commercial type
for technical use, as was used in the investigation of
the equilibrium diagram.

Temperatures were measured with a Chromel-Alumel
thermocouple of 16 B a S gauge wire and an L. & N. direct
reading potentiometer with manual reference junction
compensator.

The heats were melted in graphite crucibles and
poured into permanent molds made of % inch steel pipe
which were split and wired together. (Figure 24) The
bottom was a plug of alundum cement baked in at a
temperature of 1400-15000F. The mold had a small pouring
basin of alundum which would be easily crushed if the
longitudinal contraction was great enough. The bottom 2
inches of the mold were packed in a mixture of crushed
refractory and asbestos as a precaution in case the mold

should “bust out.“

(Z

PROCEDURE

The aluminum slugs were weighed and a corres-
ponding amount of antimony weighed out to make the
necessary concentration. The a1uminum.was then placed
in a graphite crucible and melted. The molten alum-
inum was poured into another graphite crucible con-
taining the antimony and this second crucible returned
to the furnace and the mixture superheated to lSOOOF.
(with the exception of one of two samples containing
1.0% antimony whieh was heated to 13oo°F.)

The molten metal was then poured into the mold
at a rate such that the basin was full at all times and
the basin was left full after the mold was filled to
allow some metal for contraction, in an effort to prevent
the formation of pipes if possible. All the samples were
poured into the same type of mold.

After being allowed to cool in the mold, one of
the two bar s of the .05% antimony composition was heated
to 1200°F. and quenched in water.

The bars were then machined to the specifications
shown in Figure 25.

The diameter of the bars was measured and a 2"
gauge length punched on the bars. The bars were broken
in a .3311 hand operated Dillon tensile testing machine
using serrated chucks. The bars were then put togOther
and held in place in a vise while the elongation was

measured. This was done by means of a pair of dividers

73

and a set of outside calipers accurate to 3.001 inches.
The diameter after rupture was measured by micrometer on
one of the broken sections. Then approximately % inch

was ground from the portion of the tensile bar used in the

ehuek and a Brinell impression taken using the 500 kg. load.

74

TABLE_§§ PHYSICAL TESTING DATA

 

 

 

 

Composition Tensile Elongation Reduction Brinell
;Z Antimony Strength 9: Area fiardness
0 5,620 * s 24.9
.05 8,690 35.5 21.9 29.7
4 .05 3,160 * s 32.6
.10 7.900 30.9 26.1 28.4
.20 9,130 50.6 49.5 29.7
.30 8,800 * s 29.7
.40 8,340 30.5 18.5 23.8
.50 8,490 35.3 29.6 21.8
.60 9,100 40.1 46.0 31.2
.70 9,710 50.9 64.5 31.2
.80 ** as as «a
.90 9,500 55.9 64.8 29.7
1.00 9,170 39.3 31.9 29.7
$4 1.00 11,140 51.9 56.5 29.7
1.10 7,150 27.4 18.8 24.9

*

for 15 days 2% hours.

Broken outside 2“ gauge marks.

Quenched from 12000F. Aged at room temperature

Broke while machining.

Heated to 1300°F. before pouring rather than

75

 

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DISCUSSICN

 

All the properties apparently follow the same
general trend, i.e., where one has a minimum in the curve
of properties vs. composition, the others do also.

At .1% antimony, the point at which all the boun-
dary eutectics and compounds appear to be in solution, a
minimum occurs in all the properties investigated. The
greatest drops in properties occur at about .4% and 1.1%
antimony. At .4% antimony the dark gray constituent has
appeared in long angular form, and the equilibrium dia-
gram shows the liquidus rising from the point at .3%
antimony. At 1.1% antimony the light gray constituent
appears in a long angular shape which is not confined
to the grain boundaries. Apparently these two constituents
are embrittling in their nature.

The properties appear to be at their maximum at
.05%, .2%-.3%, and .6%-.9% antimony. At .05% antimony the
boundary eutectic has increased slightly. At .2%-.3%
antimony the dip occurs in the liquidus curve which may or
may not be a eutectic. The microstructures show eutectic,
but this may be predominately impurity phases. At .6%-.9%
antimony the microstructure is predominately of the black
phase which progresses toward a eutectic formation almost
entirely occuring at the grain boundaries. Apparently this
constituent is strengthening in its nature.

The tensile bar containing .05% antimony, which was

quenched into water from 1200°F. and aged at room temperature

79

for 15 days and 2% hours, had very low tensile properties.
Apparently this alloy is heat treatable, but the mechan-
ism of aging proceeds rather slowly at room temperature
and has a detrimental effect upon the tensile strength.

However, the tensile bar containing 1.0% antimony,
which was poured at l300°F. rather than 15000F., had very
good properties and even better properties than the bar
of the same composition which was poured from 15000F.
Apparently, the grain size was much smaller - which might
be inferred from the appearance of the tensile bars after
rupture. The bar poured from 15000F. had a very pro—
nounced ripple to its surface, while the bar poured from
1300°F. had a relatively smooth surface.

Three of the bars tested had imperfections, none
of which caused failure. Apparently, this alloy is notch

insensitive.

80

5. CONCLUSIONS

Antimony below 1% has very noticeable effects upon
the physical properties in very definite ranges of com-
position, as shown by Figure 22. Therefore, any effort to
strengthen aluminum with small amounts of antimony should
be closely controlled.

The effects of small additions of antimony to
aluminum are not entirely detrimental. Additions of’.6%
to .9% antimony give the maximum pr0perties. Within this
range of composition the tensile strength, ductility and
hardness are a1 1 at a maximum.

The alloys appear to be notch insensitive and the
tensile bars continued to show strength after they had split
and cracked on their external surface.

Care must be exercise d to assure complete diffusion
or antimony may separate out in the melt. This was over»
come by heating to 1500°F. However, heating to 1300°F.
gives much bette r tensile properties.

The equilibrium diagram shows limited solubility
below 0.1% antimony with the formation of at least one
eutectic. Apparently, there is some change at 0.1%
antimony, as shown by the cooling curves and the graph
of properties vs. composition. However, the metallographic
examination failed to corroborate this fact.

When viewing these facts, it would be well to
bear in mind that all the changes in temperature and

strength which are pointed out in this investigation

81

are rather small changes.

Further investigation undoubtedly should be carried
out on these alloys. A few suggestions might be: additions
to commercial alloys, condition after heat treatment, and
other physical properties such as impact strength, fatigue
strength, electrical resistance, effects on thermal ex-
pension, and machineability. The equilibrium diagram in
the region of 0.1% antimony also should be investigated
further.

85

 

PHOTQ#23
Top view cf a sprue showing a particle
of antimony which was forced there
during solidification.

 

 

77—‘_7

PHOTQ# 24

A view of tensile bars containing (topo
to bottom) .4%, .7%, 1% (heated to 13000 F. )
and 1.10% antimony, showing the surface

variation after rupture and the relative
elongation.

83

REFERENCES

Dawdell, R. L., Jerabek, H. 3., Forsyth, A.C., and
Green, C. H., 'General Metallography," New York,
John Wiley and Sons, 1943, P. 277.

 

 

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