激光熔敷Ti_5Si_3/(NiTi_2+β+Ti_5Si_3)复合涂层组织与耐磨性

Microstructure and wear resistance of laser clad Ti_5Si_3/(NiTi_2+β+Ti_5Si_3) composite coating

为了提高钛合金的干滑动磨损耐磨性能,以Ti-Si-Ni混合合金粉末为原料对BT9钛合金进行激光熔敷处理,制备出以金属间化合物Ti5Si3为耐磨增强相的快速凝固'原位'耐磨复合涂层,利用金相、SEM、XRD等技术分析了涂层的成分及显微组织结构,在室温干滑动磨损试验条件下测试了涂层的耐磨性.结果表明:涂层中Ti5Si3初生相均匀分布于NiTi2-β-Ti5Si3共晶基体上,整个涂层组织均匀、致密、无气孔、无裂纹;涂层与钛合金基材形成了良好的冶金结合,涂层具有很高的硬度,在室温干滑动磨损试验条件下具有优异的耐磨性能.

To improve the dry sliding wear resistance of titanium alloy, a wear resistant Ti5Si3 reinforced intermetallic composite coating was fabricated on substrate of titanium alloy BT9 by laser cladding using the Ni-Ti-Si alloy powders. The composition and the microstructure of the intermetallic composite coating was investigated by OM, SEM, XRD and EDS. The wear resistance of the coating was tested under dry sliding wear condition at room temperature. The results indicated that the laser clad composite coating was free from porous and microcracks and has a rapidly solidified homogeneous microstructure consisting of Ti5Si3 primary particles uniformly distributed in the NiTi2-β-Ti5Si3 eutectic matrix. The laser clad Ti5Si3/(NiTi2+β+Ti5Si3) composite coating has high hardness and excellent wear resistance under dry sliding wear test conditions.