Reversal of asymmetry of X-ray peak profiles from individual grains during a strain path change

X-ray peak profiles are measured from individual bulk grains during tensile deformation. Two differently oriented copper samples pre-deformed in tension show the expected peak profile asymmetry caused by intra-grain stresses. One of the samples is oriented to achieve a significant change of the intra-grain stresses during in situ tensile loading and this is observed as a reversal of the sign of the peak profile asymmetry.