Abstract
? 2022 Elsevier B.V.Generally, Mg-Gd alloys need to be firstly solution treated at relatively high temperatures and then artificially aged at low temperatures to achieve adequate strength, which costs dozens of hours. Herein a Mg-10Gd-0.2Zr (wt%) alloy was reported to achieve excellent strength-ductility synergy with the product of ultimate tensile strength and elongation of 2791.3 MPa × % just by laser powder bed fusion (LPBF). The excellent strength-ductility synergy is attributed to the novel multi-scale hierarchical microstructure containing heterogeneous grain structure, intragranular lamellae substructure and nano-sized precipitates. Abnormal precipitation of a large number of intragranular β1 phases with blocky shape is first found in the as-built Mg-10Gd-0.2Zr alloy. The findings demonstrate that the unique heat and strain history during LPBF can be exploited to deliberately regulate the type, area number density, morphology and distribution of precipitates, thus controlling mechanical properties.
NSTL
Elsevier