High-strength and high-modulus Al18B4O33W/GWZ1031K magnesium matrix composite prepared by squeeze casting

Abstract

High-strength and high-modulus Mg-10Gd-3Y-1Zn-0.4Zr (GWZ1031K, wt.%) alloy matrix composite reinforced with aluminum borate whiskers (Al18B4O33w) was fabricated by squeeze casting. The microstructure, interfacial characteristics, mechanical properties and fracture behavior of the composite were investigated. The results indicate that the grains of Mg matrix were significantly refined from 29±2 μm to 2 ± 0.5 μm by the randomly distributed whiskers in the composite. For the first time, two adjacent and distinct interfacial reaction layers were found between the whisker and matrix, which resulted from the interfacial reaction and element diffusion. Compared with the matrix alloy and other Al18B4O33w reinforced Mg matrix composites, the tensile strengths at room and high temperatures, Vickers hardness and Young's modulus of the composite were significantly improved. The yield strength (YS), ultimate tensile strength (UTS) and Young's modulus of the material at room temperature reached 364 ± 13 MPa, 380 ± 16 MPa and 77.8 ± 2.1 GPa respectively, realizing the integration of high strength and high modulus. The fracture analysis indicated a mixed fracture mode of macro brittle fracture and micro ductile fracture of the composite.