Effects of Alloying Element Sb on Microstructure and Mechanical Properties of AM50 Magnesium Alloys

The effect of Sb on the as-cast microstructure and mechanical properties of magnesium alloy AM50 was investigated.The results show that with increasing the addition of Sb,β phase is changed from continuous or discontinuous netlike form to strip or particulate form.When the addition of Sb is 0.5%,the as-cast microstructure is refined obviously and strip new phase Mg3Sb2 appears.With the continuous increase of the addition of Sb,Mg3Sb2 phase increases more obviously and becomes bigger.With the increase of Sb,the tensile strength of AM50 alloy first increases and then decreases,whereas the elongation tends to decrease.The fracture mechanism of AM50 alloy is changed from ductile fracture to mixed fracture and then to cleavage fracture with the addition of Sb.