AlCrN涂层的残余热应力分析

采用ANSYS有限元分析软件中的瞬态分析方法,对涂层刀具沉积过程中残余热应力进行了仿真分析。研究了AlCrN涂层残余热应力的大小、分布和影响因素。结果表明:由于涂层与基体材料的热膨胀系数不匹配,结合面区域存在严重的应力集中;基体材料、涂层厚度、沉积温度以及中间层的使用对残余应力有很大影响;基体材料为高速钢时,AlCrN涂层内残余应力大以压应力为主并随着涂层厚度的增加而减小;基体为硬质合金时,残余应力相对较小,涂层内以拉应力为主并随基体钴含量和涂层厚度的增加而减少;增加中间层可以减小残余应力。因此,通过涂层和不同基体匹配以及增加中间层可以缓和界面应力增强界面结合强度。

Thermal Residual Stress Analysis of AICrN Coating

Residual thermal stresses produced in deposition process of coating tools were calculated by using tran- sient analysis method of finite element analysis software. The residual stress level, distribution and influence factors of Al- CrN coating were studied. The results show that due to the mismatch of coefficient of thermal expansion between the coat- ing and the substrate, there is a serious stress concentration in the interface region. Different substrates, coating thickness, deposition temperature and interlayer have great influences on the residual stress. With high-speed steel as substrate, the residual stress of A1CrN coating is mainly compressive stress which increases with the diminution of coating thickness. While with carbide as substrate, the residual stress is relatively small and it is mainly tensile stress which decreases with the increase of cobalt content in carbide substrate and the increase of coating thickness. Adding an interlayer to the sub- strate can reduce the residual stress. Thus, the interface stress can be released and the interfacial bonding strength can be improved by the matching of coating and different substrates as well as adding an interlayer.