Features of superplastic deformation of 5083 + 0,2 percent Zr aluminum alloy at pre- melting temperatures

摘要

The superplastic properties and microstructural evolution of a modified 5083+0,2 percent Zr aluminum alloy with an initial grain size of 6,2 #mu#m were examined in the temperature range of 500-580 deg C and strain rates ranging from 10~(-5) up to 10~(-1) s~(-1). On the basis of the results obtained the increase in deformation temperature up to 570 deg C (approx 0,99 T_m) is shown to lead to significant changes in superplastic behavior of the alloy. Such a type of the behavior is characterized by the lack of threshold stresses, extension of an optimal interval of superplasticity towards lower strain rates, and activation energy for superplastic flow being higher than for lattice diffusion in aluminum. Mechanisms of superplasticity at pre-melting temperatures of the alloy are discussed.