顯微組織和耐磨性
(北京航空航天大學(xué) 材料科學(xué)與工程學(xué)院
激光材料加工制造技術(shù)實驗室, 北京 100083)
摘 要: 利用激光熔化沉積技術(shù)制備出分別以NiTi和Ni3Ti為初生相的NiTi/Ni3Ti金屬間化合物耐磨合金， 采用XRD、 OM、 SEM、 EDS等手段分析合金的組織， 測試合金的室溫干滑動磨損性能。 結(jié)果表明， 其室溫干滑動磨損機制為軟磨料磨損和氧化磨損； 對于以Ni3Ti為初生相的合金， 其室溫干滑動磨損機制在中低負(fù)荷下為氧化磨損和顯微切削， 在高負(fù)荷下則是Ni3Ti的顯微切削； 以NiTi為初生相的NiTi/Ni3Ti金屬間化合物合金具有更好的抗室溫摩擦磨損性能。
關(guān)鍵字: 激光熔化沉積； NiTi； Ni3Ti； 磨損； 顯微組織
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
