Influence of Grain Size on Elongation at Elevated Temperatures in AZ31 Mg Alloy

Abstract

Mechanical properties of an AZ31 Mg alloy with the grain sizes of 4, 12, 60 and 450 mm were investigated by tensile tests at 473-673 K with 1:7 Â 10 À5 -1:7 Â 10 À1 s À1 . The Mg alloy exhibited unique behaviors of low elongation of 17% at 473 K with 1:7 Â 10 À1 s À1 for the specimen with the grain size of 450 mm and large elongation of 234% at 673 K with 1:7 Â 10 À5 s À1 for the specimen with the grain size of 60 mm. These behaviors could not be explained from the viewpoint of the plastic stability. Microstructural observation revealed significant twin formation at 473 K with 1:7 Â 10 À1 s À1 for the specimen with the grain size of 450 mm and active grain boundary sliding at 673 K with 1:7 Â 10 À5 s À1 for the specimen with the grain size of 60 mm. Therefore, it is likely that enhancement of twining and grain boundary sliding gave rise to the unique behaviors of the Mg alloy that could not be explained from the plastic stability.

Influence of specimen size and sheet thickness on the material behavior of AZ31B under uniaxial tension

“…Regarding the determined grain size, which is twice as large in case of a sheet thickness of 1.5 mm, the higher reachable strains and the higher beginning of plastic yielding for a thickness of 1.0 mm are explainable by a better dislocation motion due to smaller grains. A similar influence of the grain size on the elongation behavior at 200 °C is presented by Mabuchi et al [12]. Zhu et al explained the increase of the yield stress by the effect of twinning, where the critical resolved shear stress (CRSS) increases significantly with a decrease of grain size [13].…”

Grain size dependence of dynamic mechanical behavior of AZ31B magnesium alloy sheet under compressive shock loading

“…Magnesium alloys, as the lightest structural materials, are promising lightweight materials and have a high potential for application in the transportation industry [1][2][3] to increase fuel efficiency and decrease the greenhouse gas emissions [4][5][6]. However, wrought magnesium alloys normally form a strong basal texture during manufacturing processes such as rolling which results in low room temperature ductility and therefore, their structural applications are limited [7][8][9][10].…”

Grain refinement of Mg–Al cast alloy by the addition of manganese carbonate

“…The refined microstructure in ascast components leads to a more uniform distribution of solute elements and secondary phases on a fine scale. It also provides such advantages as superior extrudability and rollability, excellent resistance to hot tearing, and good surface finish, leading to considerable cost reductions in the production of wrought magnesium parts [4][5][6][7][8].…”