Unprecedented Alternating Change in Microstructure and Texture of AZ31 Magnesium Alloy under High-Temperature Plane Strain Compression

Abstract

 AZ31 magnesium alloy specimens are deformed at 723 K with a strain rate of 5.0×10⁻² s⁻¹ in the plane strain compression mode and the effects of deformation on the texture and microstructure evolution are studied. The specimens feature three different textures unsuitable for the activation of a basal slip system. It is found that the areas of high pole density appear at 20° away from the compression plane in the (0001) pole figures when the activation of both basal and prismatic slip systems are suppressed. When the plane strain compression deformation can be achieved only by the prismatic slip systems or the first order pyramidal slip systems, a heretofore unreported phenomenon manifests: alternating changes in crystal grain structure and texture with increasing strain. It is concluded that this change can be attributed to orientation stability for the deformation and preferential growth of grains such that {1010}〈1120〉 orientation consumes {1120}〈1010〉 grains.

Fig. 4

Grain structure maps derived from EBSD measurement of specimens A, B and C deformed at 723 K with a strain rate of 5.0×10⁻²s⁻¹ up to a strain of −1.0.