显微组织和耐磨性
(北京航空航天大学 材料科学与工程学院
激光材料加工制造技术实验室, 北京 100083)
摘 要: 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。
关键字: 激光熔化沉积； NiTi； Ni3Ti； 磨损； 显微组织
laser melting deposited NiTi/Ni3Ti
intermetallic alloys
（Laboratory of Laser Materials Processing and Manufacturing,
School of Materials Science and Engineering,
Beijing University of Aeronautics and Astronautics, Beijing 100083, China）
Abstract: The wear-resistant NiTi/Ni3Ti intermetallic alloys were designed and fabricated by the laser melting deposition process. The as-solidified microstructures of the NiTi/Ni3Ti 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/Ni3Ti intermetallic alloy with NiTi dendrite as the primary phase is soft abrasion and oxidative wear, while that of the NiTi/Ni3Ti intermetallic alloy with Ni3Ti as the primary phase is oxidative wear and micro-cutting under low/medium normal load, and micro-cutting is under high normal load; the NiTi/Ni3Ti intermetallic alloy with NiTi dendrite as the primary phase has better wear resistance under dry sliding wear test conditions than that with Ni3Ti as the primary phase.
Key words: laser melting deposition; NiTi/Ni3Ti; wear; microstructure
