An analytic and generalized formulation of the sin2 ψ-method

Abstract

Abstract X-ray stress measurements can be done without the accurate knowledge of the unstressed lattice parameters, if the specimen’s surface can be assumed as stress-free and provided that the measured strains depend linearly on sin2 ψ. This is usually done in the so-called sin2 ψ method. An analytical formalism is proposed with which the same task can be performed even if the linear sin2 ψ dependence is not given. Therefore, one is completely free in choosing and combining measurement parameters φ;ψ, and (hkl). It can be used for single-crystalline, textured, texture-free, isotropic or anisotropic materials. Further advantages are an easy way for correct error calculus and a means to optimize the whole procedure for minimum errors in φ.