MICROSTRUCTURE AND MECHANICAL PROPERTIES OF NON-HEAT TREATABLE ALUMINUM ALLOYS PRODUCED BY ACCUMULATIVE ROLL BONDING PROCESS

摘要

Non-heat treatable aluminum alloys were subjected to Accumulative Roll Bonding(ARB) process for grain refinement to submicrometer levels. Microstructures after ARB and subsequent annealing treatments were observed using transmission electron microscope. Microhardness and tensile tests were conducted on ARBed alloys to examine the strength and elongation at ambient temperature. The microhardness and strengths of ARBed alloys are considerably higher than those of commercially available respective alloys. Meanwhile, elongation is greatly decreased after the first cycle and shows no further decrease with increasing the number of cycles. In the range of 2 to 5 cycles in ARB process, AA1100 alloys exhibited strain hardening behavior, but AA8011 alloy demonstrated to be transferred to strain softening behavior. The former is attributed to the dominant contribution of strain hardening, but the latter to the precipitation of Si and recovery during ARB process.