N. Freri et al., DIFFRACTION DETERMINATION OF STRESS-FIELD AND ELASTIC-CONSTANTS IN POLYCRYSTALLINE MATERIALS, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 231(1-2), 1997, pp. 10-16
A mathematical method has been developed to calculate, on the basis of
diffraction measurements only, the stress field, the unstressed inter
planar distance, d(0), the Young modulus, E, and the Poisson coefficie
nt, v, of polycrystalline materials. The feasibility of the method has
been checked on a set of 2.25CrlMo steel samples. Moreover, the propa
gation of errors associated with the system has been evaluated and dis
cussed by a Monte Carlo simulation. The results show that the calculat
ed elastic constants are greater than the macroscopic constants, which
points to the effect of the microstructure on the elastic properties
of polycrystalline materials. The present method has the capability to
measure the unstressed interplanar distance, this being d(0), a funda
mental problem in the determination of the stress fields by neutron di
ffraction experiments. Moreover, it is shown that the precision in the
evaluation of the stress field by diffraction methods is not strongly
affected by the uncertainty of the knowledge of E, v and d(0) paramet
ers. (C) 1997 Elsevier Science S.A.