Microstructures and tensile properties of a twin roll cast and heat-treated Mg–2.4Zn–0.1Ag–0.1Ca–0.1Zr alloy

An Mg–2.4Zn–0.1Ag–0.1Ca–0.1Zr alloy sheet, with a tensile yield strength of 316 MPa, an ultimate tensile strength of 342 MPa and an elongation of 17%, has been processed by twin roll casting (TRC), hot rolling and heat treatment. The high yield strength has been attributed to a uniform distribution of fine rod-like precipitates of MgZn2 phase. The TRC and hot-rolled sheet also showed an exceptionally high stretch formability with a limiting dome height much larger than those of other Mg alloys.