Fast evaluation of the temperature dependence of residual stress in ceramic coatings via an image relative method

Abstract

Although the residual stress in one‐side coating (type‐I coating) on a beam specimen can be determined by comparing the bending deformation before and after coating, the stress of a coated component without bending deformation (type‐II coating) is difficult to obtain via conventional methods, especially at high temperature. An image relative method is presented to determine variations in the curvature radius with temperatures for stress analysis at high temperature. A relationship between the residual stresses in type‐I and type‐II coatings was established so that the residual stress of type‐II coating was determined from the measured stress in type‐I coating. Thus, the core issue is to measure the temperature dependence of the bending deformation of the sample with one‐side coating. The temperature dependence of the residual stress in thermal barrier coatings on metal substrate was obtained by continuously photographing deflections of the beam specimen at temperatures ranging from 20°C to 1000°C, and the residual stress in components with symmetrical coatings in the temperature range was then determined.