High-pass Ecap Of Pure Copper Organization Change And Performance Research

Equal channel angular pressing at room temperature was used to impose high strain(24) into the pure copper. Microstructure conversion and Mechanical properties of ultrafine copper at high strain levels were investigated. Besides relationship between store energy and temperature of recrystallization also was investigated.The experiment results revealed that the grain size refined as the ECAP passes increased. After 12 passes, the grain size reduced to only 0.25μm, further pressing the grain size can not be refined. Under such high strain levels(>12), the continues dynamic recrystallization occurred. Research on relationship between store energy(Est) and temperature of recrystallization(Tr) showed that during the early 8 passes, the Tr reduced as the Est increased, however after 12 passes the Est reduced little and Tr retained. The tensile tests showed that the ultimate tensile strength increased as the passes increased, after 8 passes it reached the highest ,then the value of strength reduced little but soon retained. On the other hand , the ductility lost seriously after 1 pass, however it recovered slowly in the subsequent pressing. After 16 passes the ultrafine copper exhibited both high tensile strength (σ_b=420MPa) and ductility (Elongation δ=30%) at room temperature.Nowadays, ECAP technique is still a new research field in the world, and ECAP copper which less than 12 passes were studied most, however Imposing such high strain(>16) into the pure copper can improve ductility efficiently. So it can be used to obtain good mechanical properties in metals.