等离子表面Cr-Si合金化改善TiAl基合金高温性能的研究

摘要

Plasma alloying of Cr-Si on TiAl-based alloy was achieved by using Double Glow Plasma Surface alloying technology. Morphology, content of elements and phase composition were characterized by means of SEM, EDS and XRD. High temperature oxidation resistance and wear resistance of alloyed layer were also investigated. The results show that the phase in alloyed layer is composed of Cr3Si and Laves phase TiCr2. The phases in transition layer are Al8Cr5 and Al3Ti. The concentration of Cr and Si displays gradient distribution. Dense CrO2 and continuous protective Al2O3 film were formed in the process of oxidation. The curve of oxidation kinetics was parabolic. The extent of abrasive wear and oxidation wear decreased dramatically due to the plasma alloying process. Relative wear resistance of alloying layer had enhanced 17.3 times.%利用等离子表面合金化技术,在TiAl基合金表面实现了Cr-Si二元共渗.使用扫描电镜(SEM)、能谱(EDS)和X衍射仪(XRD)检测了合金渗层的形貌、合金元素含量与相组成,并研究了合金化处理对TiAl基合金高温抗氧化性能与高温耐磨性能的改善效果.结果显示,合金渗层组成相为Cr3Si及Laves相TiCr2,过渡层物相主要为Al8 Cr5与Al3 Ti,合金层内Cr,Si元素含量呈梯度分布.经高温氧化,合金渗层表层形成致密CrO2,内层形成连续Al2 O3阻隔层,其氧化动力学曲线呈现典型的抛物线型.较之原始TiAl基合金摩擦学特性,Cr-Si合金渗层的磨粒磨损程度降低极大,氧化磨损受到抑制,其相对耐磨性能提高了17.3倍.