High-temperature strength in an additively manufactured Al-based superalloy with stable nanoscale eutectic cellular networks
Siming Ma, Zhe Chen, H. Fang, Gang Ji, Mingliang Wang, Yuchi Cui, Yang Li, Shengyi Zhong, Han Chen, Yi Wu, Ying Zhou, S. Nie, Jian Lü
Abstract
Metallic materials typically experience significant strength degradation at elevated temperatures. Traditional strengthening methods, which rely on thermally stable particle dispersion, exhibit limited effectiveness owing to the challenges in suppressing thermally activated dislocation motion. This work introduces a strategy for achieving exceptional high-temperature strength through a thermally stable nanoscale eutectic cellular network (ECN) enabled by additive manufacturing. A near-eutectic AlLaScZr alloy is developed for laser powder bed fusion, incorporating an Al-La nanoscale ECN and dense intracellular nanoprecipitates. This alloy demonstrates excellent printability and remarkable high-temperature yield strength above 0.6Tm (~250 MPa at 300 °C), outperforming conventional aluminium alloys by 2–5 times with minimal degradation after prolonged annealing. Compared with the conventional configuration of particle dispersion, the nanoscale ECN architecture enhances load-bearing capacity and strengthens aluminium by caging dislocation motion within ultrafine cells (~200 nm), effectively mitigating intrinsic high-temperature softening. Metallic materials suffer severe strength degradation at elevated temperatures. The authors report exceptional high-temperature strength in an additive manufactured aluminum alloy with a thermally stable nanoscale eutectic cellular network.