The properties of MIG welding AZ91 Dcast magnesium alloy with φ1.2 mm S301 and φ1.6 mm ER5356 aluminum wire were investigated.The results reveal that two kinds of welding wires can be welded effectively in each welding specification

and a large number of Mg

17

Al

12

brittle phases can be observed in the welded zone

which affect seriously the mechanical properties of the welded zone.The relative content of the Mg based solid solution and the Mg-Al brittle phase in the welded zone is related to the ratio of local Mg and Al.By adding zinc alloy to the welding zone

it is found that zinc can reduce greadly the Mg

17

Al

12

phase in the welded zone

and MgZn

2

new phase is precipitated

which promote the growth of magnesium based solid solution.Finally

the comprehensive mechanical properties of the welding zone are improved.