Improved work hardening capability and ductility of an additively manufactured and deformed Al-Mn-Mg-Sc-Zr alloy

An Al-Mn-Mg-Sc-Zr alloy was additively manufactured and subsequently deformed to investigate the effect of high defect densities on the precipitation behavior, work hardening capability and ductility. For this, the LPBF-fabricated alloy was deformed by rotary swaging up to a true strain of 2.5 following a laser powder bed fusion (LPBF) process. Compared to the LPBF condition, swaging results in a refinement of the microstructure by one order of magnitude and an increased hardness and ultimate tensile strength (UTS) which is mainly attributed to the finer microstructure of the swaged alloy. By annealing, a higher peak-aging hardness of (209 ± 2) HV0.1 and UTS of (717 ± 2) MPa of the swaged alloy at a lower peak-aging temperature of 300 °C (1 h) was obtained. Significant improvement of uniform elongation by enhanced work hardening capability of the swaged and annealed alloy is obtained for annealing temperatures above 300 °C while strength is only moderately affected. The significant improvement of aging kinetics is discussed alongside a profound microstructural characterization of the heterogeneous grain structure and precipitate distribution.