Method for Predicting Flow Stress of Solution- and Dispersion Hardened Alloys at High Temperatures

Abstract

For clarification of the path dependence of flow stress in a solution- and dispersion hardened alloy at high temperatures, stress-strain curves were measured at 673 and 573 K for several different deformation paths using Al-3.1 at%Mg-1.3 vol%Be and Al-2.8 at%Mg-0.97 at%Mn alloys. A method for the theoretical prediction of flow stress along an arbitrary deformation path was proposed based on the deformation mechanism in a solution- and dispersion hardened alloy at high temperatures. The theoretical stress-strain and creep curves were compared with the experimental ones.
The results are summarized as follows.
(1) The flow stress strongly depends on the deformation path in the same manner as solution hardened alloys without dispersoid.
(2) The dispersion hardening component ‾σ_i^p depends on the flow stress σ as
(This article is not displayable. Please see full text pdf.)
\ oindentwhere ‾σ_i^d is the mean internal stress due to dislocation interaction, σ_v the void hardening stress, x_c the maximum bowing-out distance of dislocation between the particles, and ‾l_s the mean particle spacing on the slip plane.
(3) The predicted curves agree well with the experimental ones, as long as the solute atmosphere drag mechanism operates.