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目的 提出一种由连续叠加热失配应力和曲率淬火应力组成的新型涂层表面残余应力预测模型,用于预测高速电弧喷涂成形过程涂层表面残余应力值.方法 基于高速电弧喷涂层逐层叠加成形基本假说,利用力和力矩平衡原理,分别建立了涂层逐层叠加热失配应力模型和淬火应力模型,将两模型组合后,得出喷涂过程涂层表面残余应力数值模型.结果 通过与X射线衍射仪测得的不同厚度FeAlCrBSiNb涂层表面残余应力值进行比较,发现喷涂一道次时,涂层表面残余应力值为涂层形成过程中最大表面残余应力值.喷涂层厚度为500μm前后,涂层表面残余应力变化规律不同,即理论预测值与实际值随喷涂厚度的增加先减少,当喷涂厚度沉积至500μm后,理论预测值趋于有增有降的波动平稳,而实际测量值在厚度增加至1500μm后逐渐下降.结论 高速电弧喷涂过程涂层表面残余应力预测模型,可以较为准确地预测涂层形成过程中表面最大残余应力值和涂层厚度小于500μm时的涂层表面残余应力值,揭示出高速电弧喷涂层实际成形过程表面残余应力的分布规律,即随着喷涂层沉积厚度的增加,残余应力先减少而后沉积至500μm后略微增大.

The work aims to predict surface residual stress during forming process of high velocity arc spraying by propos-ing a new prediction model made up of continuous thermal mismatch stress and curvature quenching stress for surface residual stress on coatings. Models of continuous thermal mismatch stress and quenching stress curvation were established, respectively, based on force and moment equilibrium principle as well as overlapping coating hypothesis. Numerical model of residual stress on the sprayed surfaces was obtained after these models were combined. Comparing the predicted values with measured residual stresses on the sprayed surfaces by XRD indicated that, surface residual stress of the coating after one time spraying was the maximum during coating formation process. Varying pattern of surface residual stress differed as coating thickness was nearly 500μm, i.e., both theoretical predicted values and measured values firstly decreased as spraying thickness increased. As the spraying thickness of coatings deposited up to 500μm, the theoretical results were subject to stationary fluctuation while meas-ured value increased to 1500μm and decreased gradually. This new prediction model can accurately predict the maximum resi-dual stress and residual stress of thicker coatings with thicknesses less than 500μm. The distribution law of residual stress on the formed coating surface is revealed, i.e., the residual stress first decreases and then increases slightly as it deposited to 500μm as depositing thicknesses of the coating increased.