Effects of SPS Sintering Pressure on Microstructure and Tribological Properties of 60NiTi Alloy

Abstract:

60NiTi alloys were fabricated by spark plasma sintering (SPS) at 1000 ℃. The effects of the sintering pressure on the microstructure, microhardness and tribological properties of 60NiTi alloys were also investigated. The phase structures and microstructures of 60NiTi alloys were analyzed by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The microhardness and tribological properties of 60NiTi alloys at different sintering pressure were evaluated by microhardness tester and ball-on-disk wear tester. The wear volumes were calculated by three-dimensional white light profilometer. The wear morphologies of 60NiTi alloys were analyzed by SEM with energy disperse spectroscopy (EDS) and three-dimensional white light profilometer. The experimental results showed that the microstructures of 60NiTi alloy prepared by SPS was uniform and the NiTi phase and Ni3Ti phase were presented in the microstructures. The microhardness of 60NiTi alloys were increased with the increase of the sintering pressure. The microhardness of 60NiTi alloys has the biggest value of 534 HV0.2kg at the sintering pressure of 50MPa. The wear rate and wear scar depth of 60NiTi alloys decreased as the sintering pressure increased. However, when the sintering pressure reached to 50MPa, the wear rate and wear scar depth of 60NiTi alloys are the smallest, which are 0.76×10-6 mm3/N?m and 15 μm, respectively. The wear mechanisms of 60NiTi alloys were abrasive wear and adhesive wear through the wear surfaces analysed by SEM and EDS.