MIG welding microstructure, residual stress and mechanical properties of powder metallurgy 7A52 aluminum alloys

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The MIG welding of in-situ generated nano-Al 2 O 3 powder metallurgy 7A52 (PM 7A52) aluminum alloy was investigated. The microstructure was characterized using EBSD and TEM, while macrotexture and internal residual stresses were analyzed with a self-developed SWXRD technique. The results revealed that PM 7A52 aluminum alloy effectively reduced the grain size, dislocation density, and texture strength in the post-weld microstructure. Furthermore, the residual stress in the weld zone (WZ) of PM 7A52 aluminum alloy was reduced by 38 MPa compared to that of the conventional melt-cast 7A52 (CM 7A52) aluminum alloy. Notably, the tensile strength and elongation of welded joints in PM 7A52 aluminum alloy were increased by approximately 15% and 26%, respectively. The improvement in joint tensile strength was primarily attributed to grain boundary strengthening and dispersion strengthening caused by γ -Al 2 O 3 particles entering the WZ.