激光熔化沉积NiTi/Ni3 Ti金属间化合物合金的显微组织和耐磨性

利用激光熔化沉积技术制备出分别以NiTi和Ni3Ti为初生相的NiTi/Ni3Ti金属间化合物耐磨合金,采用XRD、OM、SEM、EDS等手段分析合金的组织,测试合金的室温干滑动磨损性能。结果表明,其室温干滑动磨损机制为软磨料磨损和氧化磨损;对于以Ni3Ti为初生相的合金,其室温干滑动磨损机制在中低负荷下为氧化磨损和显微切削,在高负荷下则是Ni3Ti的显微切削;以NiTi为初生相的NiTi/Ni3Ti金属间化合物合金具有更好的抗室温摩擦磨损性能。

Microstructure and wear resistance of laser melting deposited NiTi/Ni3Ti intermetallic alloys

The wear-resistant NiTi/Ni_3Ti intermetallic alloys were designed and fabricated by the laser melting deposition process.The as-solidified microstructures of the NiTi/Ni_3Ti intermetallic alloys were characterized by X-ray diffraction(XRD),optical microscope(OM),scanning electron microscope(SEM) and energy dispersive spectrometer(EDS).The wear resistance of the alloys was evaluated under room-temperature dry sliding wear test condition coupling with hardened bearing steel GCr15.The results indicate that the room temperature dry-sliding wear mechanism of the NiTi/Ni_3Ti intermetallic alloy with NiTi dendrite as the primary phase is soft abrasion and oxidative wear,while that of the NiTi/Ni_3Ti intermetallic alloy with Ni_3Ti as the primary phase is oxidative wear and microcutting under low/medium normal load,and micro-cutting is under high normal load;the NiTi/Ni_3Ti intermetallic alloy with NiTi dendrite as the primary phase has better wear resistance under dry sliding wear test conditions than that with Ni_3Ti as the primary phase.