CREEP BEHAVIOR OF AN ALUMINUM-7034 ALLOY PROCESSED BY ECAP

摘要

Processing by equal-channel angular pressing (ECAP) of a commercial Al-7034 alloy at a temperature of 473 K gives an ultrafine grain size of ～0.3 μm and superplastic elongations of more than 1000% at high strain rates (·10~(-2)s~(-1)) when testing at 673 K. The creep behavior of the as-pressed alloy was investigated at temperatures of 473, 573 and 673 K and the results are plotted as strain rate against flow stress. The experimental data are examined with emphasis on the strain rate range associated with superplastic elongations. The creep behavior of the alloy in the as-received condition was also evaluated. The results show good agreement with a theoretical model for grain boundary sliding under superplastic conditions.