Aspects of power law flow rules in crystal plasticity with glide-climb driven hardening and recovery

Abstract

In this work we will examine three power law type flow rules that are commonly used in crystal plasticity. Glide and climb driven combined hardening/recovery effect has been considered within their respective internal variables. With finite strain framework, a highly complex intermetallic material (single crystal like Al-rich TiAl lamellar binary alloy) has been analyzed at high homologous temperature. We have adopted a novel approach of estimating critical stresses and modified evolution equation for the combined hardening and recovery. From a variety of options in identifying modeling parameters, which set of flow rule dependent parameters are meaningful is discussed here. Different related numerical aspects including slip activities are also outlined. The investigation employs three sets of compressive strain rate controlled experimental data in two lamellar directions. It is revealed that, irrespective of the type of the flow rules, two internal variables based flow rules including slip-system-level kinematic hardening variable makes significant improvement in simulating high temperature medium stress viscoplasticity with estimating reasonable material parameter set, and a specific choice of the flow rule provides better prediction capability. It is also found that the most active slip system dictates the overall plastic deformation in reproducing experimental data.