Self-Consistent Determination of Time-Dependent Behavior of Metals

Abstract

Though Kröner’s self-consistent model is not fully consistent in the elastic-plastic deformation of polycrystals, it is found to be perfectly consistent in the time-dependent deformation of such materials. Hill’s model, on the other hand, should be used with a modified constraint tensor containing the elastic moduli of the matrix in that case. Kröner’s model is supplemented with a physically consistent constitutive equation for the slip system; these, together with Weng’s inverse method, form the basis of a self-consistent determination of time-dependent behavior of metals. The kinematic component of the latent hardening law and the residual stress introduced in more favorably oriented grains are the two major driving forces for recovery and the Bauschinger effect in creep. The proposed method was applied to predict the creep and recovery strains of a 2618-T61 Aluminum alloy under pure shear, step and nonradial loading. The predicted results are seen to be in generally good agreement with the test data.