Measurment and estimation of residual stress distribution in thim films and coatings

1. x射线穿透深度当厚度大于有效x射线穿透深度的6倍时，应根据整个薄膜衍射x射线的强度，用加权平均应力分析应力梯度2。基于衍射角与x射线倾角sin^2psi （psi= x射线倾角）之间的非线性关系，提出了一种新的x射线应力测量方法来确定陶瓷地面下残余应力的分布。考虑表面粗糙度对应力测量值的影响，采用Bezier曲线确定残余应力分布。新方法测得的残余应力分布与表面去除法测得的残余应力分布基本一致。热障涂层薄膜（TBC-film）由于TBC薄膜的孔隙和裂纹的存在，除了表现出弹性行为外，还表现出滑动和非线性行为。为了测量TBC薄膜的残余应力，需要TBC薄膜的测试方法。

1. X-ray penetration depthThe stress gradient should be analyzed by the weighted average stress on the basis of the intensity of the diffracted X-rays from the entire thin film, when the thickness is six times larger than the effective X-ray penetration depth2. Analysis on residual stress distribution ground ceramiceA new method of X-ray stress measurement was proposed to determine the distridution of residual stress beneath the ground surface of ceramics from the non-linear relation between the diffraction angle and the sin^2psi (psi=the X-ray inclination angle). By taking account of the effect of the surface roughness on the measureed stress value, the Bezier curve was applied to fid the residual stress distribution. The residual stress distribution determined by the new method agreed with the residual stress distribution measured by the surface-removal method.Thermal barrier coating film (TBC-film)TBC film show slipping and nonlinear behavior in addition to elastic behavior due to pores and cracks of TBC films. To measure residual stresses of TBC films, the testing method for TBC film is needed.