Optimization of conflicting properties via engineering compositional complexity in refractory high entropy alloys

SCRIPTA MATERIALIA

卷:199

Article

Kim, Il Hwan¹  Oh, Hyun Seok^1,2  Lee, Kwang Seok³  Park, Eun Soo¹ 

[1] Seoul Natl Univ, Res Inst Adv Mat, Dept Mat Sci & Engn, Seoul 08826, South Korea

[2] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA

[3] Korea Inst Mat Sci, Chang Won 51508, South Korea

关键词: Refractory high entropy alloy;    Atomic size misfit parameter;    Valence electron concentration;    Strength-ductility trade-off;    Thermal conductivity;   

DOI  :  10.1016/j.scriptamat.2021.113839

来源: Elsevier

【 摘 要 】

The strength-ductility (or thermal conductivity) trade-off is unavoidable in most conventional alloys due to the limited composition space. Herein, we propose a mechanism-based design strategy for concurrent optimization of high temperature (HT) strength, room temperature (RT) ductility, and HT thermal conductivity by considering atomic size misfit for solid-solution hardening and lattice distortion, and valence electron concentration for shear instability. As a test case, we extend the composition space of binary WTa alloys to W-Ta-V-Ti-Cr refractory high entropy alloys (RHEAs), and the present RHEAs (e.g. WTaVTiCr) exhibit superior HT strength (1210 +/- 43 MPa at 1073 K) and RT ductility (23.4 +/- 5.7%). Further, we show that the thermal conductivities of the present RHEAs increase with increasing temperature, and theoretically can reach to similar to 40% of that of pure W at 2000 K. This work thus provides a general design rule of RHEAs that enables effective utilization of compositional complexity for potential applications. (c) 2021 Published by Elsevier Ltd on behalf of Acta Materialia Inc.

【 授权许可】

Free