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arXiv · 1911.10975

Natural-mixing guided design of refractory high-entropy alloys with as-cast tensile ductility

Shaolou Wei·Sang Jun Kim·Ji Yun Kang·Yong Zhang·Yongjie Zhang·Tadashi Furuhara·Eun Soo Park·Cemal Cem Tasan
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Abstract

Multi-principal-element metallic alloys have created a growing interest that is unprecedented in metallurgical history, in exploring the property limits of metals and the governing physical mechanisms. Refractory high-entropy alloys (RHEAs) have drawn particular attention due to their (i) high melting points and excellent softening-resistance, which are the two key requirements for high-temperature applications; and (ii) compositional space, which is immense even after considering cost and recyclability restrictions. However, RHEAs also exhibit intrinsic brittleness and oxidation-susceptibility, which remain as significant challenges for their processing and application. Here, utilizing natural-mixing characteristics amongst refractory elements, we designed a Ti38V15Nb23Hf24 RHEA that exhibits >20% tensile ductility already at the as-cast state, and physicochemical stability at high-temperatures. Exploring the underlying deformation mechanisms across multiple length-scales, we observe that a rare beta prime precipitation strengthening mechanism governs its intriguing mechanical response. These results also reveal the effectiveness of natural-mixing tendencies in expediting HEA discovery.

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Shaolou Wei, Sang Jun Kim, Ji Yun Kang, Yong Zhang, Yongjie Zhang, Tadashi Furuhara, Eun Soo Park, Cemal Cem Tasan. 2019-11-25. Natural-mixing guided design of refractory high-entropy alloys with as-cast tensile ductility. https://doi.org/10.1038/s41563-020-0750-4

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