The influence of extrusion temperature on the structures and mechanical properties of Mg–Al–4Y alloys

Abstract

Abstract In this study, Mg–Al–4Y alloys were successfully prepared via the melting and casting method. The alloys were then extruded at 450 °C, 500 °C, and 550 °C. The influence of the extrusion temperature on the microstructures and mechanical properties of the alloys was investigated. The results indicated that the Al2Y phase was coarse and agglomerated in the Mg matrix. A strong {0001} basal fiber texture was formed in the alloys extruded at 450 °C; meanwhile, the alloy grains were refined, and the Al2Y phase was distributed uniformly in the matrix; these combined occurrences dramatically enhanced the strength and hardness of the alloys. As the extrusion temperature was increased from 450 °C to 550 °C, the yield strength, tensile strength, and hardness of the alloys gradually decreased, but the elasticity significantly increased. The yield strength reduced from 209.6 MPa to 197.8 MPa, the tensile strength reduced from 311.5 MPa to 271.1 MPa, and the hardness reduced from 77.5 HB to 62.2 HB, while the ductility increased from 2.9% to 15.0%. Based on the experimental results, the high strength and hardness of the alloys were mainly due to fine grain strengthening, second phase strengthening, and {0001} basal fiber texture strengthening.