About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
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Symposium
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Additive Manufacturing of Metals: Microstructure, Properties and Alloy Development
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Presentation Title |
Microstructure Development and Creep Resistance of Selective Laser Melted Al-Fe-Mn-Si-Zr Alloy |
Author(s) |
Jovid Rakhmonov, Nhon Q Vo, Joseph Croteau, Joshua Dorn, David Dunand |
On-Site Speaker (Planned) |
Jovid Rakhmonov |
Abstract Scope |
Phase transformations during solidification and subsequent aging of selective laser melted (SLM) Al-Fe-Mn-Si-Zr alloy (Addalloy HT alloy from NanoAL) are investigated using SEM, S/TEM and 3D-APT. Its mechanical properties are assessed at 20 and 300 °C via hardness and creep testing, respectively. Microstructural investigations reveal a bimodal grain structure, with ultrafine equiaxed grains at melt pool bottom and coarser, columnar grains at melt top/center. Grain boundaries throughout the melt pool are extensively decorated by α-Al(FeMn)Si precipitates formed during solidification, and the grain interiors exhibit L12-Al3Zr nanoprecipitates formed upon aging. This complex grain/precipitate microstructure allows for both excellent room-temperature strength and outstanding creep resistance. The creep resistance of Al-Fe-Mn-Si-Zr is compared to other cast and SLM Al alloys in both diffusional and dislocation creep regimes, and it is rationalized by considering the role of precipitates in (i) preventing grain-boundary sliding, (ii) inhibiting dislocation movement and (iii) providing load sharing with α-Al. |