旋转速度对6082铝合金搅拌摩擦焊接头组织及性能的影响OA

In order to optimize the friction stir welding process parameters for 6082-T6 aluminum alloy and elucidate the influence of rotation speed on the welding joint quality,a 4 mm thick 6082-T6 aluminum alloy plate was selected as the research material.Under the condition of fixed other welding parameters,the effects of three rotation speeds 600 r/min,750 r/min,and 950 r/min on the microstructure and mechanical properties of the joint were systematically investigated through metallographic analysis,microhardness testing,and tensile testing.The results show that as rotational speed increases,the weld nugget zone expands,the"S"shaped flow pattern and onion ring structure gradually diminish,dynamic recrystallization becomes more complete,and the equiaxed grains are refined.The Mg2Si strengthening phase exhibits reduced particle size,increased quantity,and a more dispersed and uniform distribution.In the heat-affected zone,grain coarsening and precipitate coarsening are observed.Microhardness distributions of the joints exhibit a characteristic"W"shape,with the lowest values located in the heat-affected zone.As the rotation speed increases,the microhardness of the nugget zone,the tensile strength and the elongation of the joint all increase.At a rotational speed of 950 r/min,the joint achieves optimal mechanical properties,with a tensile strength of 211.5 MPa and an elongation of 4.51%.The fracture location of the joints transfers to the heat-affected zone under these conditions.These findings provide valuable technical guidance for optimizing the friction stir welding process of 6082 aluminum alloy.