Hierarchical microstructure strengthening in a single crystal high entropy superalloy
Yung-Ta Chen, Yao-Jen Chang, Hideyuki Murakami, Taisuke Sasaki, K. Hono, Chen-Wei Li, Koji Kakehi, Jien-Wei Yeh, An‐Chou Yeh
Abstract
Abstract A hierarchical microstructure strengthened high entropy superalloy (HESA) with superior cost specific yield strength from room temperature up to 1,023 K is presented. By phase transformation pathway through metastability, HESA possesses a hierarchical microstructure containing a dispersion of nano size disordered FCC particles inside ordered L1 2 precipitates that are within the FCC matrix. The average tensile yield strength of HESA from room temperature to 1,023 K could be 120 MPa higher than that of advanced single crystal superalloy, while HESA could still exhibit an elongation greater than 20%. Furthermore, the cost specific yield strength of HESA can be 8 times that of some superalloys. A template for lighter, stronger, cheaper, and more ductile high temperature alloy is proposed.