热喷涂涂层和基体中残余应力预报与控制研究

分析研究了热喷涂涂层和基体中残余应力产生的原因并发展建立了相应的理论模型.依据该模型,不但可以计算骤冷过程和冷却过程在涂层/基体结构内引发的残余应力,而且首次分析了沉积过程中,基体/涂层因喷射冲击(即喷涂粒子高速撞击基体及形成的涂层表面)而产生的残余应力,以及因基体/涂层热膨胀系数不匹配产生的残余应力.理论计算结果与实验结果基本吻合.通过理论计算,可以预报涂层/基体中残余应力的大小,并根据需要控制涂层/基体中残余应力的分布.对即将进行的热喷涂工艺具有一定的指导意义.

PREDICTION AND CONTROL OF RESIDUAL STRESSES IN THERMAL SPRAYED COATINGS

An analytical model is developed to predict and control the residual stress distributions in deposited coatings and substrate by thermal spraying.Not only the residual stresses in coatings and substrate during quenching and cooling processes,but also for the first time the residual stress in coatings and substrate arising from spraying impact(i.e.spraying particles impacting coatings and substrate at high speed,),as well as the residual stress arising from misfit thermal expanding coefficients of substrate and coatings during the whole deposition process are calculated.The calculated results basically agree with the experiment results.With the theoretical prediction of residual stresses in coatings and substrate,the residual stress distributions in coatings and substrate can be controlled.The present work is of some guiding significance for thermal spraying process.