MICROSTRUCTURAL EVOLUTION OF CU-AG IN-SITU COMPOSITES PROCESSED BY EQUAL CHANNEL ANGULAR PRESSING (ECAP)

摘要

Equal-channel angular pressing (ECAP) technique has been proven to be very useful in improving strength of ingot-processed metallic alloys and composites through grain refinement to, typically, the submicrometer level. Although ECAP processing has been employed extensively to many metals and alloys, application of ECAP to in situ composites is quite limited. Recently, Cho and Hong and Tian et al. studied the effects of processing routes on the microstructure and mechanical properties during ECAP of Cu-Ag in-situ composites. Since the microstructure Cu-Ag in-situ composites consist of two phases, the microstructural refining by severe plastic deformation is more effective than pure metals because the dislocation annihilation is limited by the presence of second phase. Furthermore, the second phase in Cu-Ag in-situ composite is ductile and deformed to accommodate the imposed strain during deformation processing, the redistribution of Ag phase renders the higher strength to Cu-Ag in-situ composites.