High temperature deformation characteristics of equal channel angular pressed AA6082-T6

Abstract

High temperature deformation behavior of 6082AA that was over aged and pressed to 6 passes in equal channel angular die via route C was investigated. High-temperature tensile deformation was conducted in the range of 753 to 823K at four strain rates in the range of 10−2–6×10−1s−1. Stress dependence of the strain rate revealed a stress exponent, n of 7 throughout the ranges of temperatures and strain rates tested. The apparent activation energy was calculated to be 223kJmole−1. These findings implied the presence of threshold and by incorporating the threshold stress in the analysis, the true activation energy was calculated to be about 139kJmol−1. A plot of normalized strain rate (ε̇kT/DGb) vs. normalized effective stress (σ–σo)/G, on a double logarithmic scale, gave an n value of 5. Ductility increased with strain rate for all the temperature ranges and maximum ductility value of 173% was achieved at 823K for 6×10−1s−1.