"The purpose of this thesis is to investigate the possibility of attaining the self-healing property in metallic alloys produced by the 3D printing technology. Stainless steel (SS) is used as our metal system and the copper element is added to improve the self-healing property. The sintering additive of 0.5% of boron was found to improve the final density dramatically and reduce the sintering temperature, enabling us to improve the mechanical properties. This boron additive was used to print the Fe-Cu alloys. After the printing procedure, the samples are then cut into a dog-bone shaped tensile sample whose surfaces are polished before the fatigue test. During the fatigue test, we recorded the stress-number of cycle (S-N) diagram. Knowing the limit of the S-N diagram, specimens were taken to the fatigue cycle near the limit to produce minor damages/cracks. After that, the healing process of heating the specimen is applied to improve in their fatigue behavior. With the addition of 3% of Cu element, the self-healing property of steel can be enhanced dramatically. Under 407 MPa of stress, the sample without the inclusion of Cu breaks after 79019+76274 cycles, where the first number means the preloading cycles while the second one indicates the life cycles until it breaks after the heat treatment. While the performance of the sample with 3% of Cu can reach to 86893+118147 circles under 419 MPa of stress. The self-healing mechanism of Fe-Cu alloys comes from that the copper atoms can diffuse into the iron matrix to heal the microscopic cracks, which enable us to achieve 'self-healing'."--Page ii.
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