MoSi2涂层残余应力和结合强度的有限元分析

目的研究残余应力对MoSi2涂层结合强度的影响。方法基于粉末包渗法(PC)制备的MoSi2涂层在退火前后的微观形貌和相组成,建立有限元分析模型,计算MoSi2涂层在退火前后的残余应力。根据涂层法向和切向残余应力随涂层厚度的变化,并结合涂层在退火前后结合强度随涂层厚度的变化规律,研究残余应力对涂层结合强度的影响。结果有限元模拟结果表明,MoSi2涂层的法向残余应力随涂层厚度的增加而减小。涂层的切向残余应力在涂层界面边缘处形成应力集中,并且最大切向残余应力随涂层厚度的增加而增大,与涂层结合强度的变化趋势相吻合。此外,退火后,MoSi2涂层的法向残余应力几乎没有变化,但是最大切向残余应力下降了10%左右,结合强度提高了20%左右。结论粉末包渗法(PC)制备的MoSi2涂层的结合强度受切向残余应力的影响,涂层切向残余应力增大,导致涂层结合强度降低。退火处理能够起到有效改善涂层界面切向残余应力集中的作用,对于提高涂层结合强度有明显的效果。

Finite Element Analysis of Residual Stress and Bonding Strength of MoSi2 Coating

The work aims to investigate the effect of residual stress on bonding strength of MoSi2 coating. Based on the microstructure and phase composition of MoSi2 coating prepared by packing cementation (PC) before and after annealing, the corresponding finite element analysis model was established to calculate the residual stress of the coating before and after annealing. According to the variation of the normal and tangential residual stress of the coating with the thickness of the coating, the influence of the residual stress on the bonding strength of the coating was studied by the change of the bonding strength before and after annealing with coating thickness. The results of finite element simulation showed that the normal residual stress of coating decreased with the increase of coating thickness. The tangential residual stress of coating formed a stress concentration at the edge of coating interface, and the maximum tangential residual stress increased with the increase of coating thickness, which was consistent with the change trend of coating bonding strength. In addition, the normal residual stress of MoSi2 coating barely changed after annealing, but the maximum tangential residual stress decreased by about 10%, and the coating bonding strength increased by about 20%. The bonding strength of MoSi2 coating prepared by packing cementation (PC) is affected by tangential residual stress. The increase of tangential residual stress of coating leads to the decrease of bond strength of coating. Annealing treatment can greatly improve the tangential residual stress concentration at the interface of coating, and it has obvious effect on improving the bonding strength of coating.