Microstructure, mechanical properties and fracture behavior of a new WE43 alloy

The microstructures, mechanical properties and fracture behaviors of a new WE43 alloy (Mg–4Y–1.6Nd–2Sm–0.5Zr) were investigated. The microstructure of the as-cast alloy includes a Mg matrix, Mg₄₁Sm₅, Mg₄₁Nd₅ and Mg₂₄Y₅ eutectic phases, as well as β-phase. After an optimal solution treatment, the eutectic phases are almost completely dissolved; only a few spots of blocky Mg–Y compounds remain at grain boundaries. After an aging treatment, a large amount of β′-phases are dispersed and precipitated at the grain interior, which provides good comprehensive mechanical properties of the alloy, particularly in the under-aged state. The tensile strength is up to 290 MPa, the yield strength reaches 209 MPa, and the elongation is slightly improved. Furthermore, the fracture behaviors of the studied alloy in different states significantly differ. In addition, a comparison of mechanical properties of the new WE43, traditional WE43 and other modified WE43 alloys is presented.