激光熔敷Ti5Si3／NiTi金属间化合物复合材料涂层组织与耐磨性

Microstructure and Wear-Resistant Properties of Laser Clad Ti5Si3/NiTi Intermetallic Composite Coating

摘要:

以Ti14Si6Ni80合金粉末为原料，利用激光熔敷技术在BT9钛合金表面制得以金属硅化物Ti5Si3为增强相、以金属间化合物NiTi为基体的快速凝固金属间化合物复合材料涂层，分析了该涂层的显微组织，在室温干滑动磨损条件下测试了其耐磨性。研究结果表明，涂层硬度高、组织致密、与基材之间为完全冶金结合，在干滑动磨损试验条件下具有较好的耐磨性。涂层具有优异耐磨性的主要原因是作为耐磨增强相的金属硅化物Ti5Si3具有高硬高耐磨的特性，在涂层中起到了抗磨骨干作用，同时作为涂层基体的金属间化合物NiTi由于具有极强的原子结合键及应力诱发马氏体相变特性，本身具有优异的耐磨性，在摩擦过程中对耐磨增强相Ti5Si3起到了强力支撑作用。

Abstract:

A novel rapidly solidified Ti 5 Si 3 /NiTi intermetallic composite coating was fabricated on substrate of a t itanium alloy BT9by laser cladding using the Ni-14Ti-6Si allo y powders.Microstructure of the coa ting was characterized by OM,SEM,XR D and EDS.Wear resistance of the coating was tested under dry sliding wear condition at room tempera ture.The results indicate that the l aser clad intermetallic composite coating has a homogeneous rapidly so lidified microstructure consistin g of Ti 5 Si 3 primary particles uniformly distributed in the NiTi matrix,and is metallurgically bonded to the titanium substrate.The laser clad inte rmetallic composite coating has hig h hardness and excellent wear re-sistance under dry sliding wear test condition.The excellent wear resis tance of the laser clad Ti 5 Si 3 /NiTi intermetallic composite coating is attributed to the high hardness and s trong atomic bonding of the reinforc ing Ti 5 Si 3 phase and to the strain-induced martensite transformation of the NiTi intermetallic matrix.