The microstructure of deformed nanocrystalline Ag and Ag/Fe alloy

Structures of alloys prepared by an inert-gas condensation and compaction m ethod and subsequently rolled were examined with interest in the deformatio n mechanism. The initial grain size is found to be smaller in the alloy tha n in the single component material, but XRD measurements indicate that a no rmal preferred orientation of rolling is developed in the Ag/Fe alloy sligh tly but not in the Ag at all. The grain growth occurs more or less but hard ness is not increased by deformation in both materials. Strain contrasts al ong grain boundaries are observed by TEM, but tangled dislocations are foun d in grain interior of neither of the deformed materials. The observation h as indicated that the dominant mechanism of deformation in the examined nan ocrystalline materials, especially in the single component material, is con sidered to be grain boundary sliding accomplished by a diffusional process. (C) 2000 Acta Metallurgica Inc.