Unexpected high-temperature brittleness of a Mg-Gd-Y-Ag alloy
Lirong Xiao, Xuefei Chen, Huiyan Ning, Ping Jiang, Yi Liu, Bin Chen, Dongdi Yin, Hao Zhou, Yuntian Zhu
Abstract
Rare earth (RE) can produce excellent precipitation hardening in Mg alloys. However, when forming a solid solution, it also deteriorates formability, a problem that can usually be overcome by raising deformation temperature. Here we report an unexpected observation of high temperature brittleness in a Mg-Gd-Y-Ag alloy. As the temperature reached 500 °C, the formability decreased drastically, leading to severe intergranular fracture under only 0.5% strain. This was caused by failure of grain boundaries, which are weakened by segregated interfacial compounds.
Topics & Concepts
Materials scienceFormabilityAlloyIntergranular corrosionMetallurgyBrittlenessGrain boundaryStrain hardening exponentPrecipitationComposite materialMicrostructureMeteorologyPhysicsMagnesium Alloys: Properties and ApplicationsAluminum Alloys Composites PropertiesMetal and Thin Film Mechanics