Twinning and Texture Evolution in Binary Mg-Ca and Mg-Zn Alloys

Texture evolution and formability in binary Mg-Ca and Mg-Zn alloys have been investigated in the present study. Static recrystallization during annealing treatment of rolled sheets leads to increase of basal pole intensity in Mg-3Zn alloy, but decrease in Mg-xCa alloys (x=0.05, 0.1 and 0.5). With increasing Ca content in Mg-xCa alloys, the basal texture becomes weaker, indicating that Ca is one of the effective elements in weakening the basal texture in Mg alloys. The effect of Ca on weakening the basal texture mainly comes from the presence of Ca atoms in the alpha-Mg solid solution matrix rather than from the Mg2Ca particles formed during solidification. More frequent occurrence of compression (or double) twins results in weakening of the basal texture possibly due to lower stacking fault energy in Mg-Ca alloy than in Mg-Zn alloy. The room temperature formability of Mg-Ca alloy is highly superior to that of the Mg-Zn alloy.