Texture, Structure, Mechanical Properties, and Deformability of MA2-1pch Magnesium Alloy Rolled Sheets Preliminarily Subjected to Direct Extrusion or Equal-Channel Angular Pressing and Annealing

Resumo

The textural and structural evolution in MA2-1pch magnesium alloy sheets fabricated from initial workpieces after (1) hot direct extrusion or (2) equal-channel angular pressing performed by route B_c in four passes at 245°C and subsequent recrystallization annealing is investigated during warm rolling and subsequent uniaxial tension. The same sharp basal texture, but different structures with different average grain sizes and fractions of twinned grains form in sheets (made of two different workpieces) after warm rolling. Subsequent uniaxial tension arranges basal planes in the sheets made from workpiece 2 along prismatic directions. Modeling of texture within the framework of a thermoactivation model shows that the texture changes due to the activation of prismatic slip. Structural evolution during uniaxial tension in the sheets made of workpiece 2 is accompanied by more intense twinning than that in the sheets made of workpiece 1. These textural and structural changes are responsible for the enhanced mechanical properties and the deformability parameters of the sheets fabricated from workpiece 2.