摘要
A friction stirring welding to joint 5 mm rolled AZ31 magnesium had beendeveloped. The microstructures in various regions including the weld nugget, thermo-mechanicallyaffected zone (TMAZ) and heat affected zone (HAZ) were investigated and compared with unaffectedparent metal using optical microscopy. The results showed that the heat and mechanical process hadgreat effect on the microstructure evolution. In weld nugget, the heat was enough to producesufficient superplastic material flow and the mechanical effect was greatest, and the dynamicrecrystallization was completed thoroughly. In TMAZ, the mechanical effect was indirectly affectedby the welding tool and only some grains had undergone dynamic recrystallization. The variousregions were studied in detail to better understand the microstructure evolution during frictionstirring welding (FSW). The cross section near the 'key hole' showed clear onion rings because thematerial was stirred only by the rotation of the probe and materials rotated with the probe and didnot move along welding direction and in vertical direction, there was no material flow and the flowmovement can be regarded as two dimensional layer flow.
A friction stirring welding to joint 5 mm rolled AZ31 magnesium had beendeveloped. The microstructures in various regions including the weld nugget, thermo-mechanicallyaffected zone (TMAZ) and heat affected zone (HAZ) were investigated and compared with unaffectedparent metal using optical microscopy. The results showed that the heat and mechanical process hadgreat effect on the microstructure evolution. In weld nugget, the heat was enough to producesufficient superplastic material flow and the mechanical effect was greatest, and the dynamicrecrystallization was completed thoroughly. In TMAZ, the mechanical effect was indirectly affectedby the welding tool and only some grains had undergone dynamic recrystallization. The variousregions were studied in detail to better understand the microstructure evolution during frictionstirring welding (FSW). The cross section near the 'key hole' showed clear onion rings because thematerial was stirred only by the rotation of the probe and materials rotated with the probe and didnot move along welding direction and in vertical direction, there was no material flow and the flowmovement can be regarded as two dimensional layer flow.
基金
ThisprojectwasfinanciallysupportedbytheNational863ProjectFoundation(No.2002AA331160).
