專  題  演  講

題目: An Introduction of High-entropy Alloys (HEAs) and Phase Transformation/Deformation Behavior in a B2-base HEA

講員：廖楷輝院士 (Prof. Peter. K. Liaw)

時間；8/5，10：00-12：00

地點：E1-102

Abstract

An introduction of high-entropy alloys (HEAs) will be presented. Ordered intermetallic compounds have long been of interest as potential structural materials for use at elevated temperatures. Among them, B2 aluminides exhibit a wide range of interesting properties, such as high ordering temperature, corrosion resistance, and pseudo-elasticity effect. However, the lack of room-temperature ductility limits their applications due to an insufficient number of independent slip systems and poor grain-boundary (GB) cohesion. To overcome this issue, here we design a B2-base HEA with a minor ductile face-centered-cubic (FCC) phase as a GB adhesive phase. The designed B2-based HEA exhibits outstanding strength and enhanced ductility at room and high temperatures. The enhanced ductility at room temperature results from the improved slip capability and stress-induced martensitic transformation of the multicomponent B2 phase, alleviating the need for five independent dislocation slip systems, as evidenced by our in-situ neutron diffraction, transmission-electron microscopy, and Monte-Carlo (MC) simulation results. The present work offers insights into alloy-design strategies that could improve the ductility of intermetallic alloys and accelerate their engineering applications.

Keywords: High-entropy alloys, intermetallics, ductility, phase transformation