PRODUCTION OF ULTRA-FINE GRAINED BULK ALUMINUM ALLOYS BY ACCUMULATIVE ROLL-BONDING (ARB) PROCESS

摘要

1100 and 5083 aluminum alloys were highly strained by the Accumulative Roll-Bonding (ARB) process, which is a novel high-straining process for bulk materials. In ARB process, the rolled material is cut, stacked and rolled again. The stacked sheets are bonded during rolling simultaneously (roll-bonding). ARB of 1100 and 5083 alloys was successfully carried out on the condition that the reduction per cycle was 50% and the rolling temperature was 473K. After several cycles of ARB, ultra-fine grains whose grain sizes are less than 1μm formed in the both materials. The volume fraction of the ultra-fine grains increased with increasing the number of cycles, i.e., strain. Electron diffraction patterns showed that they are the polycrystals with large misorientations. The mean grain sizes of the 1100 after 8 cycles and the 5083 after 7 cycles were 670nm and 280nm, respectively. The ARBed materials with ultra-fine grains showed very high strength, i.e., 300MPa for 1100 after 6cycles and 550MPa for 5083 after 7cycles.