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Abstract: AZ31B
magnesium alloy is welded by AC spot welder, mechanical properties and
microstructure of the joints are studied. The results showed that
tensile shear load of joints change regularly with increasing of welding
variables and the optimum is up to 2 097 N. The surface conditions have
significant influence on the properties of joints. There are single fine
equiaxle crystals in the nugget, of which the structure is b -Mg17Al12
precipitated on a-Mg boundaries induced by non-equibrium freezing, and
hot cracks in the joints. Fracture analysis results show the
characteristic that dimples tear along intercrystallines.
Key words:AZ31B
Mg alloy Spot-welding Mechanical properties Microstructures
Crack
CLC No: TG406
国家863计划资助项目(2002AA331160).
Received 20030630, received in revised form 20030927
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