Strain induced grain boundary premelting due to heavy pile-up of screw dislocations in deformed copper bicrystals

Grain boundary premelting occurs at very low temperatures of a half of the bulk melting point, 0.5TM[K], along the grain boundaries against which dislocations, especially screw dislocations, heavily pile up, in thin foils of deformed pure fcc metals will relatively low stacking fault energies such as copper, nickel, silver and brass. We call the above phenomena strain induced grain boundary premelting (SIGBPM). SIGBPM occurs even in bulk copper bicrystals deformed in compression at about 0.5TM, or deformed at room temperatures and then annealed at similar temperatures. Due to the SIGBPM crackings form along the grain boundaries against which screw dislocations mainly piled up heavily.