Forming Quality and Mechanical Properties of Rare Earth ModifiedAl-Mg Alloy Produced by Laser Powder Bed Fusion

Author of the article:DU Lei, XIAO Meili, FU Yanfei, KE Linda, XU Ganghao

Author's Workplace：Shanghai Spaceflight Precision Machinery Institute, Shanghai 201600, China

Key Words：laser powder bed fusion; forming quality; microhardness; tensile properties; Al-Mg-Sc-Zr alloy

Abstract：An Al-7.5Mg-0.48Sc-0.162Zr-0.48Mn alloy was produced via laser powder bed fusion (LPBF). The mechanismof the influence of the forming process parameters on the forming quality was discussed, and the influence of the heattreatment process on the microhardness and tensile properties was revealed. The results show that the relative density of theLPBF-processed Al-Mg-Sc-Zr samples reach 99.8% at the optimized forming process parameters. With increasing energydensity, the size of the molten pool gradually increases. Excessive energy density leads to the formation of circular pores,whereas low energy density leads to the formation of irregular pores. The microhardness of the LPBF-processedAl-Mg-Sc-Zr alloy increases with increasing heat treatment time. After annealing at 325 ℃ for 9 h, the microhardnessincreases to 158.7 HV0.1, which is 30.3% greater than that of the as-built samples. After annealing at 325 ℃ for 2 h, theLPBF-processed Al-Mg-Sc-Zr alloy achieves excellent tensile properties, with a tensile strength of 538 MPa and elongationof 9%.