Martensitic Alloy EP-823 was subjected to different levels of cold-reduction. The cold-worked materials were analyzed for characterization of the resultant residual stresses by positron annihilation spectroscopy. Efforts were also made to characterize dislocations in these cold-worked materials by transmission electron microscopy, and to correlate them to the residual stresses characterized by the PAS technique. This indicated that the dislocation density was increased at higher levels of cold-reduction, which was associated with enhanced residual stress in terms of a line-shape parameter determined by positron annihilation spectroscopy.

Relationship of Residual Stress to Dislocation Density in Cold-Worked Martensitic Alloy. A.K.Roy, S.Bandyopadhyay, S.B.Suresh, D.Maitra, P.Kumar, D.Wells, L.Ma: Materials Science and Engineering A, 2006, 416[1-2], 134-8