Microstructure And Property Of Friction Stir Welding Jiont For3003Aluminumalloy

In this paper,3mm thick3003aluminum alloy sheet, part of them was annealing.Annealing temperature was538°C, holding time was3h. Annealing and not annealing ofthe material were used CNC welding equipment in the air,20°C water,0°C coolingwater under different control to reverse friction stir welding. The effect of differentcontrolled cooling methods on the mechanical property of different zone at the joint wasinvestigated. The conclusions are as followed:Under differently controlled cooling conditions, the microstructure of welding nuggetzone and thermal-mechanical affect zone both changed remarkably. The grain size ofwelding nugget zone is smaller than that of the base material whose smallest in0°C water,then in20°C water and last in air. The range of heat affect zone at joint is wider with theincreasing environmental temperature and obvious boundary with base material emerged.In the second phase analysis, we find that the main phase precipitates are MnAl6andFeMnAl6phases, volume fraction of the second phases particle in heat plate matrixfriction stir welded joints is larger than that in hot-rolled plate joint. Grains in the finalformation organization, is mainly large-angle grain boundaries.Under differently controlled cooling conditions, obvious changes occurred to theproperty of friction stir welding joint. In the same cooling condition, the tensile strengthand toughness of hot rolled joint is greater than that of heat-treated plate joints. The tensilestrength and toughness of the joint were both improved with the decreasing environmentaltemperature. The tensile fracture surface exhibit ductile fracture feature dominated bydimples.As the FSW, the main change of the texture of nugget zone was the R-cube, Goss andBrass. And the B side and C side of the texture relative to the texture of weldedsymmetrical distribution of nuclear area; layers of different thickness, the weld strength ofthe internal relative to the surface increased.