The development of advanced titanium alloys capable of operating above 600°C remains a critical challenge for aerospace propulsion systems,where conventional Ti alloys suffer from insufficient high-temperature st...The development of advanced titanium alloys capable of operating above 600°C remains a critical challenge for aerospace propulsion systems,where conventional Ti alloys suffer from insufficient high-temperature strength and microstructural instability.Here,we propose a computationally driven design strategy for titanium-based medium-entropy alloys(MEAs)that integrates thermodynamic phase prediction with mechanistically informed strength modeling,enabling systematic exploration of the Ti-Nb-Al-Cr quaternary system.The optimized Ti7oNbioAl15Cr5 MEA exhibits exceptional performance metrics:18%room-temperature ductility(as-cast),a yield strength of 520.7 MPa at 650°C(post-aging),and an ultralow density of 4.76 g/cm³(45%lighter than Inconel 718).Microstructural characterization reveals a metastable single-phase BCC structure in the as-cast state,which transforms into a BCC/TiAl dual-phase system upon aging,with temperature-dependent precipitate morphology and phase stability.The alloy demonstrates superior high-temperature strength retention up to 900°C(>80 MPa yield strength),outperforming commercial titanium alloys(e.g.,Ti-1100,TG6)and bridging the performance gap between conventional Ti alloys and nickel-based superalloys.This work establishes a multi-criteria design paradigm for entropy-engineered alloys,offering a viable pathway to lightweight,high-temperature structural materials for next-generation aerospace applications.展开更多
基金funding from the National Natural Science Foundation of China (NSFC, 52331006)the Hebei Natural Science Foundation (E2024105020) for financial support。
文摘The development of advanced titanium alloys capable of operating above 600°C remains a critical challenge for aerospace propulsion systems,where conventional Ti alloys suffer from insufficient high-temperature strength and microstructural instability.Here,we propose a computationally driven design strategy for titanium-based medium-entropy alloys(MEAs)that integrates thermodynamic phase prediction with mechanistically informed strength modeling,enabling systematic exploration of the Ti-Nb-Al-Cr quaternary system.The optimized Ti7oNbioAl15Cr5 MEA exhibits exceptional performance metrics:18%room-temperature ductility(as-cast),a yield strength of 520.7 MPa at 650°C(post-aging),and an ultralow density of 4.76 g/cm³(45%lighter than Inconel 718).Microstructural characterization reveals a metastable single-phase BCC structure in the as-cast state,which transforms into a BCC/TiAl dual-phase system upon aging,with temperature-dependent precipitate morphology and phase stability.The alloy demonstrates superior high-temperature strength retention up to 900°C(>80 MPa yield strength),outperforming commercial titanium alloys(e.g.,Ti-1100,TG6)and bridging the performance gap between conventional Ti alloys and nickel-based superalloys.This work establishes a multi-criteria design paradigm for entropy-engineered alloys,offering a viable pathway to lightweight,high-temperature structural materials for next-generation aerospace applications.
