Dissimilar Joining of Laser Powder Bed Fusion AlSi10Mg Alloys to Wrought Al–Mg Alloys Using Cold Metal Transfer Welding

In the present study, cold metal transfer welding is conducted to join laser powder bed fusion (L‐PBF) AlSi10Mg alloys with conventional Al–Mg alloys and Er and Zr modified Al–Mg (Al–Mg–Er–Zr) alloys, respectively. The porosity, microstructural evolution, and mechanical properties of dissimilar AlSi10Mg/Al–Mg and AlSi10Mg/Al–Mg–Er–Zr joints are investigated. The results show that the AlSi10Mg/Al–Mg–Er–Zr joint exhibits reduced porosity in the weld metal (WM), decreasing from 2.4% to 2.1%, compared to the AlSi10Mg/Al–Mg joint. The AlSi10Mg/Al–Mg–Er–Zr joint exhibits significant microstructural improvements in the WM, including grain refinement, a lower Schmid factor, and a higher geometrically necessary dislocation density. The ultimate tensile strength (UTS) values of the AlSi10Mg/Al–Mg and AlSi10Mg/Al–Mg–Er–Zr joints are 187.6 and 203.3 MPa, respectively. This demonstrates that the AlSi10Mg/Al–Mg–Er–Zr joint achieves a significantly higher UTS, which can be primarily attributed to the reduced porosity, grain refinement, and enhanced solid solution strengthening in the WM.