Wire arc additive manufacturing of Al-Mg-Sc alloy: An analysis of the effect of Sc on microstructure and mechanical properties

Al-Mg-Sc alloy was deposited by wire arc additive manufacturing (WAAM). The influence of Sc on the micro-structure and mechanical properties of deposited alloys was studied. The results show that supersaturated so-lution Sc precipitated as Al3Sc phase during deposition due to the WAAM thermal cycle. After the addition of Sc, a transformation from columnar grains to equiaxed grains occurred in the deposited Al-Mg alloy, accompanied by a significant reduction in grain size. The mechanical properties improved due to the change of the grain morphology and grain size refinement. In addition, the microstructure of the deformation sample shows that the uniformly dispersed Al3Sc particles hinder the dislocation motion. It means that precipitation strengthening also improves the mechanical properties of deposited Al-Mg-Sc alloy. The yield strength, ultimate tensile strength, and elongation of the deposited Al-Mg-Sc alloy are 183.03 MPa, 335.58 MPa, and 22.74%, respectively. Compared with the deposited Al-Mg alloy without Sc, it increased by 88%, 55%, and 46%, respectively.

Automated summary

Al-Mg-Sc alloy was successfully deposited by wire arc additive manufacturing (WAAM). The addition of Sc resulted in a transformation from columnar grains to equiaxed grains, accompanied by a significant reduction in grain size, which improved the mechanical properties of the deposited alloy. The uniformly dispersed Al3Sc particles hindered the dislocation motion, contributing to precipitation strengthening. The deposited Al-Mg-Sc alloy exhibited a yield strength of 183.03 MPa, ultimate tensile strength of 335.58 MPa, and elongation of 22.74%, which increased by 88%, 55%, and 46%, respectively, compared to the deposited Al-Mg alloy without Sc.