EFFECT OF ANNEALING TEMPERATURE ON DYNAMIC DEFORMATION BEHAVIOR OF ULTRA-FINE-GRAINED ALUMINUM ALLOYS FABRICATED BY EQUAL CHANNEL ANGULAR PRESSING

Abstract

The influence of annealing treatment on dynamic deformation behavior of ultra-fine grained aluminum alloys was investigated in this study. After equal-channel angular pressing at 200 degrees C, most of the grains were considerably reduced to nearly equiaxed grains of 0.3 mu m in size. With an increment of various annealing treatments for 1 hour, resultant microstructures were found to be fairly stable at temperatures up to 200 degrees C, suggesting that static recovery would be dominantly operative, whereas grain growth was pronounced above 250 degrees C. The tensile test results showed that yield and ultimate tensile strengths decreased, but elongation-to-failure and strain hardening rate increased with increasing annealing temperature. The dynamic deformation behavior retrieved with a series of torsional tests was explored with respect to annealed microstructures. Such mechanical response was analyzed in relation to resultant microstructure and fracture mode.