The Fiber Laser Welding Research For Magnesium Alloy Of ZK60 And MB8

ZK60 magnesium alloy has good mechanical properties,but its price is higher,and MB8 magnesium alloy has good corrosion resistance,using MB8 magnesium alloy instead of ZK60 magnesium alloy can reduce the cost and improve the joint corrosion resistance.For this reason,this article test the same and heterogeneous ZK60 and MB8 magnesium alloy sheet separately with optical fiber laser welding,analysising of the effect of process parameters on welded joint macro morphology,microstructure,mechanical properties,fracture position,fracture morphology,and inspecting of welded joint surface defects with the penetration testing.The test results show that,the weld microstructure of ZK60 magnesium alloy is small equiaxed dendrites,which is made up of α-Mg matrix and MgZn2 phase;The weld microstructure of MB8 magnesium alloy is equiaxed dendrites and columnar dendrites,which is made up of α-Mg matrix and Mn phase;The weld microstructure of ZK60 and MB8 dissimilar weld is equiaxed dendrites and columnar dendrites,which is made up of α-Mg phase.When the process parameters is improper,there is a small amount of porosity.For ZK60 magnesium alloy welded joint,the highest tensile strength can reach about 92.1% of the base metal,the microhardness is lower near the fusion line,fracture occurs in the center of the weld area near to the fusion line,fracture presents ductile fracture of mixed fracture morphology;For MB8 magnesium alloy welded joint,the highest tensile strength can reach about 83.1% of the base metal,the microhardness is lower near the fusion line,fracture occurs near the weld center,fracture were showing quasi-cleavage brittle fracture morphology.For ZK60 and MB8 magnesium alloy welded joint,its strength is greater than the welded joint of MB8 magnesium alloy,and in a wider range of process parameters,the joint tensile strength is greater than the MB8 base metal tensile strength,the microhardness is lower near the fusion line of MB8 side,the fracture occurrs in the center of the weld to MB8 base metal area,fracture were showing quasi-cleavage brittle fracture morphology.