Microstructure and mechanical properties of Al-Mg-Mn-Er-Zr alloys fabricated by laser powder bed fusion. (October 2022)

• Record Type: Journal Article
• Authors: Guo, Yanwu; Wei, Wu; Shi, Wei; Zhou, Xiaorong; Wen, Shengping; Wu, Xiaolan; Gao, Kunyuan; Zhang, Dongyun; Qi, Peng; Huang, Hui; Nie, Zuoren
• Is Part Of: Materials & design. Volume 222(2022)
• Publication Date: 2022-10
• Subjects: Aluminum alloys -- Additive manufacturing -- Hot cracking -- Er-Zr modification -- Er-Zr synergism; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.111064
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Increasing Er content could reduce crack density in Al-Mg alloy fabricated by laser powder bed fusion. Al3 Zr particles with L12 structure promote the formation of equiaxed grains and refine the grain size. Er-Zr synergistic effect promotes the precipitation of Al3 (Er, Zr) and improves the tensile properties during aging treatment. The Al-6Mg-0.7Mn-0.4Er-1.2Zr alloy has a strength of more than 500 MPa after heat treatment and has a cost advantage. Abstract: This paper centers on high-strength Al-Mg-Mn-Er-Zr alloy, which was developed through the addition of Er, a cheap rare earth element, and suitable for additive manufacturing (3D printing). The microstructure and mechanical properties of Al-Mg-Mn-Er-Zr alloy of as-built and heat treated samples have been characterized, which shows: the precipitation of Al3 Zr primary phase at the boundary of molten pool promotes heterogeneous nucleation and refines the grains, which suppresses the formation of solidification cracking in Al-Mg alloy. To bring the Er-Zr synergistic effect into play during the aging heat treatment, the nano-scale precipitation phase of Al3 Er that diffuses nucleation at an earlier stage promotes the precipitation of Zr, leading to the formation of Al3 (Er, Zr) core-shell structure and enhancing precipitation strengthening effect. Under the combined effects of multiple strengthening mechanisms, the yield strength could reach 440 ± 3 MPa; tensile strength, 520 ± 2 MPa and elongation 15.5 ± 1.0 %.