Refinement Strengthening of AZ31 Magnesium Alloy by Warm Constrained Groove Pressing

Abstract

The grain refinement and its effect on the mechanical properties of AZ31 magnesium alloys were investigated. The grain refinement was conducted using one of the severe plastic deformation methods, warm constrained groove pressing (CGP) technology. The effective strain was analyzed using the DEFORM-3D software. It was found that the effective strain distribution in AZ31 sheet was homogeneous after a complete four-stage of CGP at 473 K. The average grain size was reduced from 20 μm to 9 μm and the hardness was improved from 55.84 HBW to 69.16 HBW after a complete CGP process at 473 K. The yield stress and ultimate tensile strength increase with grain refinement, from 132 MPa and 240 MPa to 155 MPa and 285 MPa, respectively, following the Hall-Petch relationship. Subjected to annealing at 530 K for 15 minutes, the average grain size of CGP sample decreases slightly and the elongation increased up to 16.2%, close to 17.72% for the pre-CGP samples.

DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14392