Method for measuring residual stress in substrate

Abstract

The invention discloses a method for measuring the residual stress of a substrate, which comprises the following steps: determining the parameters of temperature difference, a coating to be measured and the substrate; calculating the distance delta between a bending moment axial line and the coating, the curvature K of the bending moment axial line and the substrate interface, and the strain component epsilon s of planar direction caused by the plane stress of the substrate; calculating the straining of the substrate according to the formula that epsilon s is equal to epsilon s+K(z+epsilon); and calculating the residual stress sigma s inside the substrate according to the formula that sigma s is equal to Es'epsilon s. The method not only can accurately measure the residual stress value inside the substrate of common multilayer coating, but also can accurately measure the residual stress value inside the substrate of the functional gradient coating according to the elastic mechanic principle, and provide effective theoretical basis for the optimal design before preparing the coating.

Description

technical field [0001] The invention relates to a method for measuring residual stress, in particular to a method for measuring residual stress of a coating substrate. Background technique [0002] With the development of coating technology, the design idea of ​​multilayer coating and functional gradient coating has been incorporated into the preparation of coating, and has been widely used in modern industry. However, due to the thermal expansion coefficient mismatch between the coating and the substrate, the coating and the substrate will deform as the temperature changes, and residual stress will be generated inside the coating and the substrate, and these residual stresses will seriously affect the fatigue life of the coating. And other properties, and there will be mutual influence between the coating and the substrate. For example, the physical parameters and thickness of the coating material have a great influence on the residual stress of the substrate. It can be se...

AI Technical Summary

Problems solved by technology

However, due to the thermal expansion coefficient mismatch between the coating and the substrate, the coating and the substrate will deform as the temperature changes, and residual stress will be generated inside the coating and the substrate, and these residual stresses will seriously affect the fatigue life of the coating. and other properties, and there will be mutual influence between the coating and the substrate. For example, the physical parameters and thickness of the coating material have a great influence on the residual stress of the substrate.

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