Residual stress depth profiling of a coated WC-Co hardmetal – Part II of II: Regression methods for stress depth profile reconstruction from diffraction data

Abstract Reconstruction of residual stress depth profiles from diffraction data depends crucially on the underlying assumptions regarding X-ray elastic constants, stress state, and generic shape of the stress depth profile. This article addresses two issues: first, how to account for X-ray elastic constants varying according to different crystallographic planes by rearranging the underlying equation system such that it becomes amenable to linear regression again; second, how to construct the residual stress depth profile via inverse Laplace transformation of a piecewise linear approximation function, thereby obtaining maximum flexibility in the description of the generic shape of the profile. The methods are discussed by means of typical examples.