Determination of Residual Stresses in WCu Gradient Materials

Residual stress measurements were carried out on copper–tungsten gradient materials bymeans of neutron diffraction on the High Resolution Fourier Diffractometer on IBR-2,JINR, Dubna. The samples so far investigated had a concentration profile that approximatesthe gradient by step functions. The results show an averaged positive stress (stretch)in the copper phase and negative (compression) in the tungsten phase. A comparison toanalytical linear elastic calculations shows that the measured values are nearly an order ofmagnitude too low, whereas however, a qualitative agreement of the stress distributionexists. That this quantitative discrepancy can be attributed to the model's simplifyingassumption of pure elastic behaviour can be shown by recent calculations that also includeplasticity and show a much better agreement with the experimental values. Single peakevaluation also strongly suggests that plasticity does indeed play a significant role.