Cracks formed along boundaries, and along deformation bands in the interior of grains, in bulk bicrystals which had been compressed at room temperature and annealed in vacuum (823K) without unloading. It was suggested that the cracks formed along grain boundaries and deformation bands due to strain-induced pre-melting. That is, when localized regions with high dislocation densities were formed close to grain boundaries or deformation bands, the regions could melt at homologous temperatures of about 0.5. Pre-melting cracks along deformation bands were found here for the first time, and it was concluded that the development of pre-melting cracks was closely related to the duration of the compressive load, with no large drop during heating.

Strain-Induced Premelting at Grain Boundaries and Deformation Bands in Copper Bulk Bicrystals. M.Ohmori, T.Okada, F.Inoko: Materials Transactions, 1999, 40[9], 946-9