中国激光, 2015, 42 (10): 1003004, 网络出版: 2022-09-24
Ti6Al4V合金激光熔覆复合涂层的摩擦学和高温抗氧化性能研究
Study on Tribology and High-Temperature Oxidation Resistance of Laser Cladding Composite Coatings on Ti6Al4V Alloy
激光技术 激光熔覆 复合涂层 摩擦学 高温抗氧化性 laser technique laser cladding composite coating tribology high temperature oxidation resistance
摘要
为了改善Ti6Al4V 合金的摩擦学和高温抗氧化性能,预置NiCr/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TiC、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、NiO 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。
Abstract
In order to simultaneously improve the high-temperature wear and oxidation resistance of Ti6Al4V alloy, the composite coatings are prepared on the surface of Ti6Al4V alloy by laser cladding with the precursor mixed NiCr/Cr3C2- Al- Si powder. Microstructure, wear and high temperature oxidation resistance of laser cladding coatings are analyzed. The results show that TiC, Ti5Si3 and Cr3Si particulate reinforced γ - Ni/Al8Cr5 matrix composite coatings are formed. The average micro- hardness of the composite coating is 750 HV0.5, and is almost twice as much as that of Ti6Al4V alloy. At room temperature, compared to Ti6Al4V alloy, the composite coating exhibits excellent tribological property due to its high hardness. While at high temperature of 600 ℃ , the formation of protective transferred layers between the sliding surface of Ti6Al4V alloy and the ceramic couple can play a positive self-lubrication role. Compared with the Ti6Al4V alloy, the wear resistance of the composite coating has slight decrease because of the formation of micro-cracks on the worn surface at high temperature. After isothermal oxidation tests at 800 ℃ for 32 h, the Ti6Al4V alloy is oxidized quickly because of the high affinity of Ti towards O and the non- protective oxide scales of TiO2. The composite coating can form continuous Al2O3, NiO and Cr2O3 oxide scales on the surface, which is more protective than TiO2. The high- temperature oxidation resistance of the laser cladding composite coating is approximately 8.4 times higher than that of the Ti6Al4V alloy.
余鹏程, 刘秀波, 陆小龙, 朱刚贤, 陈瑶, 石皋莲, 吴少华. Ti6Al4V合金激光熔覆复合涂层的摩擦学和高温抗氧化性能研究[J]. 中国激光, 2015, 42(10): 1003004. Yu Pengcheng, Liu Xiubo, Lu Xiaolong, Zhu Gangxian, Chen Yao, Shi Gaolian, Wu Shaohua. Study on Tribology and High-Temperature Oxidation Resistance of Laser Cladding Composite Coatings on Ti6Al4V Alloy[J]. Chinese Journal of Lasers, 2015, 42(10): 1003004.