The effects of Ca and Mn on the microstructure, texture and mechanical properties of Mg-4 Zn alloy

The microstructural evolution,texture and mechanical properties of nine Mg-4Zn-x Ca-y Mn alloys (x=0.3,0.6,1.0;y=0.2,0.3,0.7 wt.%)were investigated systematically.Alloying with Ca and Mn refined the grains of the extruded sheets and increased the un DRX fraction.Mn could be the heterogeneous nucleation site of Ca2Mg6Zn3phase because of a good atom matching at the orientation relationship of ■.The traditional texture weakening effect of Ca was strongly decreased for the simultaneously addition of Mn.With increasing Ca and Mn concentration,the strength increased and ductility decreased.Mg-4Zn-0.6Ca-0.7Mn exhibited a good combination of ultimate tensile strength (320 MPa),yield strength (286 MPa) and elongation (16%).A model of strengthening indicated that grain boundary strengthening and precipitate strengthening made a large contribution to the strength of Mg-4Zn-0.6Ca-0.7Mn.In addition,the dynamic recrystallization,texture modification and the strengthening effect from different parts also have been analyzed in detail.