Development of Precipitation-Strengthened Al0.8NbTiVM (M = Co, Ni) Light-Weight Refractory High-Entropy Alloys

Kangjin Lee; Yunjong Jung; Junhee Han; Sung Hwan Hong; Ki Buem Kim; Peter K Liaw; Chanho Lee; Gian Song

doi:10.3390/ma14082085

Development of Precipitation-Strengthened Al_0.8NbTiVM (M = Co, Ni) Light-Weight Refractory High-Entropy Alloys

Materials (Basel). 2021 Apr 20;14(8):2085. doi: 10.3390/ma14082085.

Authors

Kangjin Lee¹, Yunjong Jung¹, Junhee Han², Sung Hwan Hong³, Ki Buem Kim³, Peter K Liaw⁴, Chanho Lee⁵, Gian Song¹

Affiliations

¹ Division of Advanced Materials Engineering and Institute for Rare Metals, Kongju National University, Cheonan, Chungnam 330-717, Korea.
² Korea Institute for Rare Metals, Korea Institute of Industrial Technology, 7-47 Songdo-dong Yeonsoo-gu, Incheon 406-840, Korea.
³ Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Gwangjin-gu, Seoul 143-747, Korea.
⁴ Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37916, USA.
⁵ Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

Abstract

Single-phase solid-solution refractory high-entropy alloys (RHEAs) have been receiving significant attention due to their excellent mechanical properties and phase stability at elevated temperatures. Recently, many studies have been reported regarding the precipitation-enhanced alloy design strategy to further improve the mechanical properties of RHEAs at elevated temperatures. In this study, we attempted to develop precipitation-hardened light-weight RHEAs via addition of Ni or Co into Al_0.8NbTiV HEA. The added elements were selected due to their smaller atomic radius and larger mixing enthalpy, which is known to stimulate the formation of precipitates. The addition of the Ni or Co leads to the formation of the sigma precipitates with homogeneous distribution. The formation and homogeneous distribution of sigma particles plays a critical role in improvement of yield strength. Furthermore, the Al_0.8NbTiVM_0.2 (M = Co, Ni) HEAs show excellent specific yield strength compared to single-phase AlNbTiV and NbTiVZr RHEA alloys and conventional Ni-based superalloy (Inconel 718) at elevated temperatures.

Keywords: high-entropy alloys; lightweight; mechanical properties; refractory alloys; sigma phase.

Grants and funding

in 2019/kongju national university