Effect of Fe Addition on Microstructure and Mechanical Properties of As-cast Ti(49)Ni(51) Alloy

Effect of Fe addition on microstructure and mechanical properties of as-cast Ti(49)Ni(51) alloy were investigated. The experimental results shows the microstructures of Ti(48.5)Ni(51)Fe(0.5) and Ti(48)Ni(51)Fe(1) alloys are mainly composed of TiNi matrix phase (body-centered cubic, BCC), Ti(3)Ni(4) and Ni(2.67)Ti(1.33) phases; the microstructure of Ti(47)Ni(51)Fe(2) alloy is mainly composed of BCC TiNi, Ti(3)Ni(4), Ni(2.67)Ti(1.33), and Ni(3)Ti phases; the microstructure of the Ti(45)Ni(51)Fe(4) alloy is mainly composed of TiNi, Ti(3)Ni(4) and Ni(3)Ti phases. The Ni(3)Ti nanocrystalline precipitates at the adjacent position of Ni(2.67)Ti(1.33) phase. The Ti(48.5)Ni(51)Fe(0.5) and Ti(48)Ni(51)Fe(1) alloys have high yield strength and fracture strength, and can be as the engineering materials with excellent mechanical properties. In addition, the Ti(48.5)Ni(51)Fe(0.5) alloy with the low elastic modulus and large elastic energy is also a good biomedical alloy of hard tissue implants. The fracture mechanism of the four alloys is mainly cleavage fracture or quasi-cleavage fracture, supplemented by ductile fracture. The experimental data obtained provide the valuable references in application of as-cast alloys and heat-treated samples in the future.