In contrast to the general work-hardening (WH) behavior of a polycrystalline face-centered cubic material, increase in the work-hardening rate was observed in Alloy 625 following precipitation of Ni2(Cr,Mo) and γ″ phases. A typical stage II WH behavior of a face-centered cubic single crystal was seen in this alloy, before and after the precipitation. Appearance of such WH behavior was attributed to the domination of planar slip during deformation. Transmission electron microscopy results from samples, before and after deformation, indicate that the precipitates were coherent or semi-coherent in nature and hence, partially or fully dissolved due to repeated shearing by dislocations. A gradual increase in WH rate of the alloy due to aging appears to justify the role of various types of geometrically necessary dislocations, which were formed as a result of precipitation.

Role of Dislocation Density in Raising the Stage II Work-Hardening Rate of Alloy 625. J.Mittra, J.S.Dubey, U.D.Kulkarni, G.K.Dey: Materials Science and Engineering A, 2009, 512[1-2], 87-91