Microstructure and mechanical properties of FeCoCrNiMn high-entropy alloy produced by mechanical alloying and vacuum hot pressing sintering
(1. School of Materials Science and Engineering, Fuzhou University, Fuzhou 350116, China;
2. School of Mechanical Engineering, Taizhou University, Taizhou 318000, China;
3. School of Mechanical & Electrical Engineering, Putian University, Putian 351100, China;
4. School of Materials Science and Engineering, Fujian University of Technology, Fuzhou 350118, China)
2. School of Mechanical Engineering, Taizhou University, Taizhou 318000, China;
3. School of Mechanical & Electrical Engineering, Putian University, Putian 351100, China;
4. School of Materials Science and Engineering, Fujian University of Technology, Fuzhou 350118, China)
Abstract: FeCoCrNiMn high-entropy alloys were produced by mechanical alloying (MA) and vacuum hot pressing sintering (VHPS). Results showed that the nano-crystalline alloy powders were obtained by MA and the corresponding phase structures were composed of FCC matrices and low amounts of BCC and amorphous phases. After VHPS, the BCC phases almost disappeared, simultaneously with the precipitation of σ phases and M23C6 carbides. An increase of sintering temperature resulted in grain growth of the precipitated phases. As the sintering temperature was increased from 700 to 1000 °C, the strain-to-failure of the alloys rose from 4.4% to 38.2%, whereas the yield strength decreased from 1682 to 774 MPa. The bulk FeCoCrNiMn HEAs, consolidated by VHPS at 800 °C and 900 °C for 1 h, showed relatively good combination of strength and ductility.
Key words: high-entropy alloys; microstructure; mechanical properties; powder metallurgy