It was proposed that the deposition of material at grain boundaries in tension could be used as a critical test for diffusional creep. It was generally understood that material was deposited at grain boundaries by the climb of grain-boundary dislocations. However, climb and glide were coupled processes and, since grain-boundary dislocations were associated with a step in the boundary, the movement of a grain-boundary dislocation by climb and glide would result in concurrent grain boundary migration. An experiment was described that unambiguously separated the components of deposition, grain boundary sliding and migration. The method was applied to Cu-2wt%Ni which had been crept to an elongation of 2.4% under a stress of 1.14MPa at 1073 or 1103K. It was demonstrated that material had been deposited at some of the grain boundaries which were in tension during the deformation.

Deposition of Material at Grain Boundaries in Tension Interpreted in Terms of Diffusional Creep. P.A.Thorsen, J.B.Bilde-Sorensen: Materials Science and Engineering A, 1999, 265[1-2], 140-5