不同焊接参数对7075-2A12异种铝合金FSW接头组织性能的影响OA

A friction stir welding experiment was conducted on 6mm thick 7075 and 2A12 dissimilar aluminum alloy plates with fixed AS side material of 7075,using stirring head speed and welding speed as variables,to study the changes in weld morphology,microstructure,mechanical properties,etc.under different welding parameters.The results indicate that within the experimental process parameters,the 7075-2A12 dissimilar joint welds can all be formed with varying degrees of de-fects.The WNZ microstructure of 7075-2A12 dissimilar joint has fine grains and a clear boundary with AS-TMAZ,but no clear boundary with RS-TMAZ.The TMAZ microstructure undergoes significant bending deformation.As the stirring head speed increases,the grain size of the microstructure in each area of the joint shows an increasing trend.As the welding speed increases,the grain size of the microstructure in each area of the joint shows a decreasing trend;The microhardness distribu-tion of 7075-2A12 dissimilar aluminum alloy welded joints shows an irregular"W"shape,with the AS side having higher hardness than the RS side and the WNZ side having higher hardness than the RS side base metal.As the stirring head speed increases,the welding heat input increases,and the apparent hardness,strength,and plasticity of the joint decrease.As the welding speed increases,the welding heat input decreases,and the apparent hardness,strength,and plasticity of the joint in-crease.When friction stir welding 7075-2A12 dissimilar aluminum alloy,the welding heat input should not be too large,and the stirring head speed and welding speed should be reasonably matched.The best welding speed is 50-60 mm/min matched with the stirring head speed of 600-800 r/min.