Variable strain rate sensitivity in an aluminum alloy: Response and constitutive modeling

The thermo-mechanical responses of Al 2024-T351 under uniaxial compression loading are presented. The strain rates include quasi-static regime (10(-4) to 1 s(-1)) and dynamic loading (10(3) s(-1)), at temperatures of 233 K, 296 K, 358 K, 422 K, and 505 K. Below certain threshold temperature, negligible strain rate sensitivity is observed during quasi-static regime, while significant strain rate sensitivity is measured at dynamic strain rates. Above threshold temperature, increasing strain rate sensitivity has been observed. Based on these observations, the Khan-Liu (KL) phenomenological constitutive model is proposed to predict the mechanical behavior of the alloy over wide ranges of strain rate and temperature. Correlations with this modified model are shown very close to the observed responses. (C) 2012 Elsevier Ltd. All rights reserved.