The precipitation kinetics of the α-precipitates in the Al-Mn based alloys is extremely sluggish and the precipitates are extremely coarse and form at low number densities; thus, the strength imparted is negligible. Even in a highly supersaturated SLM processed alloy, mentioned above, Mn tends to stay in the matrix if the heat treatment temperature is not sufficiently high. Our truly breakthrough discovery of Sn-assisted heterogeneous nucleation of α-precipitates in cast alloys, which leads to significant precipitation-hardening, is applicable for AM alloys. We are proposing to extend these extremely encouraging results, to other alloys processed by SLM. An order of magnitude higher supersaturation of the aluminum matrix, achieved through SLM processing, will lead to a much higher volume fraction of smaller α-precipitates, and thereby ultrahigh strengths. Employing this alloy design concept, we will perform a two-Phase study commencing with the relatively simple Al-Mn-Si-Sn alloys, strengthened with Sn-modified α- precipitates, Phase I, and proceed with multicomponent alloys, Al-Mn-Zr-(Y,Er)-Si-Sn, Phase II, utilizing a combination of the α-precipitates and L12-nanoprecipiates to create an ultra-strong aluminum alloy for ambient and high-temperature applications. We do not anticipate any deleterious interactions between the solute atoms in the multicomponent alloys proposed above, which may affect the aging response of the alloys.
|Effective start/end date||8/1/21 → 7/31/24|
- Office of Naval Research (N00014-21-1-2782)
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