Microstructure and Mechanical Properties of an Er-Modified Al–Mg–Mn–Sc–Zr Alloy Processed by Selective Laser Melting

The Al–Mg–Mn alloy modified by Sc and Zr displays exceptional properties when processed by selective laser melting (SLM). To develop high-strength and economical alloys tailored for SLM, the work herein presents the microstructure and mechanical properties of an Er-modified Al–Mg–Mn–Sc–Zr alloy processed by SLM. Near-fully dense specimen was fabricated using the optimal volume energy density of 127.95 J mm −3 . The grain size of the alloy shows a bimodal distribution where fine equiaxed grains (~ 0.660 μm) distribute at the bottom of melt pool and the epitaxially grown columnar grains (~ 3.863 μm) present a <100> fiber texture. After post-heat treatment at 375 °C for 4 h, the alloy displays an impressive strength (tensile strength of 543.5 MPa, yield strength of 524.4 MPa). The enhancement of mechanical properties is due to the coherent nanoscale Al 3 (Sc, Zr, Er) precipitates and the submicron ErMn 2 phases.