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为了改善Ti6Al4V合金的摩擦学和高温抗氧化性能,预置Ni Cr/Cr3C2-Al-Si复合粉末,采用激光熔覆技术在钛合金表面制备复合涂层。表征了涂层的显微组织结构,测试了涂层的摩擦学和高温氧化性能,并分析了相关机理。结果表明:涂层由Ti C、Ti5Si3和Cr3Si增强相及γ-Ni/Al8Cr5基体组成,平均显微硬度为750 HV0.5,约为Ti6Al4V(360 HV0.5)合金的2倍。室温(25℃)下,由于涂层的高硬度可有效抵抗塑性变形,涂层表现出较好的耐磨性能;高温(600℃)下,钛合金表面生成氧化膜,呈现自润滑效果,而涂层表面产生裂纹,耐磨性能轻微降低。恒温(800℃)氧化32 h后,钛合金表面发生严重氧化腐蚀,而涂层表面生成致密的Al2O3、Ni O和Cr2O3混合氧化物,有效阻止了氧原子的扩散,高温抗氧化性能约为钛合金基体的8.4倍。
In order to improve the tribological properties and high temperature oxidation resistance of Ti6Al4V alloy, Ni Cr / Cr3C2-Al-Si composite powders were preloaded and laser cladding technology was used to prepare composite coatings on the surface of titanium alloys. The microstructure of the coating was characterized. The tribological and high temperature oxidation properties of the coating were tested. The related mechanism was also analyzed. The results show that the coating consists of TiC, Ti5Si3 and Cr3Si reinforced phases and γ-Ni / Al8Cr5 matrix with an average microhardness of 750 HV0.5, which is about twice of Ti6Al4V (360 HV0.5). Due to the high hardness of the coating can effectively resist the plastic deformation at room temperature (25 ℃), the coating shows better wear resistance. At high temperature (600 ℃), the oxide film is formed on the surface of the titanium alloy, showing a self-lubricating effect, Coating surface cracks, wear resistance decreased slightly. After oxidation at 800 ℃ for 32 h, the surface of titanium alloy was seriously oxidized and the mixed oxides of Al2O3, NiO and Cr2O3 were formed on the surface of the coating, which effectively prevented the diffusion of oxygen atoms. The oxidation resistance at high temperature was about Ti 8.4 times the alloy matrix.