Towards a high strength aluminium alloy development methodology for selective laser melting

• Published in: Materials & design Vol. 174; p. 107775
• Main Authors: Jia, Qingbo, Rometsch, Paul, Cao, Sheng, Zhang, Kai, Wu, Xinhua
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-07-2019; Elsevier
• Subjects: Additive manufacturing; Alloy development; Aluminium alloy; Scandium; Selective laser melting; Additive manufacturing; Aluminium alloy; Alloy development; Selective laser melting; Scandium
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2019.107775

Selective Laser Melting (SLM) has received tremendous attentions due to its high degree of flexibility for the design and fabrication of geometrically complex parts. However, the majority of the currently applied metals for this advanced technology are still based on the traditional weldable and/or castable alloys, and the resulting mechanical properties of SLM fabricated samples are often mediocre. This is because the conventional alloys are not designed to accommodate the dynamic metallurgical characteristics of the SLM process and the benefits offered by SLM are not fully captured. In this study, an experimentally-based novel alloy development methodology utilising wedge mould casting and laser remelting is proposed, and the processability and properties of the developed alloys can be predicted for SLM. By mimicking the high solidification rate of the SLM process, unconventionally large amounts of solute were successfully placed into solution in the aluminium (Al) matrix. A high strength Al-Mn-Sc based alloy has been successfully developed and verified by SLM processing. The developed alloy possessed an average yield strength of about 430 MPa and a ductility of 21% in the as fabricated state, compared to approximately 570 MPa and 18% after direct ageing for 5 h at 300 °C, respectively.
[Display omitted]
•An experimental-based high strength aluminium alloy development methodology has been proposed.•High strength Al-Mn-Sc based alloys have been successfully developed specifically for SLM.•SLM fabricated Al-Mn-Sc alloy possessed a high yield strength of 570 MP a direct post-ageing treatment (300 °C for 5h).