TiAlN涂层的热残余应力分析

Thermal residual stress analysis of TiAlN coating

采用有限元方法分析氮铝钛涂层的残余热应力,研究不同的基体及过渡层对残余热应力分布的影响。结果表明:当基体为硬质合金时,涂层内以拉应力为主,而基体为不锈钢时,涂层内以压应力为主;增加过渡层可以使涂层内的残余应力减少40%以上;硬质合金基体中涂层的拉应力随基体钴含量和涂层厚度的增加而减少;无过渡层时,不锈钢基体存在明显的塑性约束区,有过渡层时,随着界面应力的减少,塑性约束区明显减小或消失。因此,通过不同的涂层和基体搭配可以改善应力场,同时增加过渡层可以缓和界面应力和增强界面结合力。

Thermal residual stresses in TiAlN coatings were calculated using the finite element method. Effects of different substrates and interlayer bonding on residual stress field were investigated. The results show that the high tensile stress occurs in TiAlN coating as the substrate is cemented carbide and the high compressive stress occurs as the substrate is stainless steel. The composites show a decrease of 40% in interface shear stress when the composites has a interlayer. The tensile stress in coating layer decreases with increasing coating thickness and cobalt content of cemented carbide substrate. Without interlayer, plastic constraint zone develops distinctly in stainless steel substrate, but the plastic constraint zone decreases greatly even disappears when there is a transition layer. Residual stress distribution can be improved by varying the coating thickness or selecting different substrates.