14:50 〜 15:10
[14D-T19-04] Microstructure and Mechanical Properties of Equimolar CrFeCoNiMo High Entropy Alloy by MM/SPS Process
キーワード：mechanical milling, spark plasma sintering, Vickers hardness
Several previous studies have shown that CrFeCoNiMo HEA has excellent strength because the intermetallic phase precipitates. However, the mechanical properties and the improvement mechanism of CrFeCoNiMo HEA produced by powder metallurgy technique are still not clear. In this paper, the microstructure and mechanical properties of equimolar CrFeCoNiMo HEA produced by mechanical milling (MM) and spark plasma sintering (SPS) process are investigated in detail. The initial and MM powders were sintered for 1.8 ks at 1173 to 1373 K and 100 MPa using SPS apparatus. The SPS compact of the initial and MM powders at 1173 K consist of FCC and m phases, while the SPS compacts at 1273 and 1373 K consist of FCC, m and s phases. It is revealed that as sintering temperature increases, the fraction of s phase increases and the fraction of m phase decrease and the Vickers hardness decreased.
Microstructure and mechanical properties of equimolar CrFeCoNiMo high entropy alloy (HEA) prepared by mechanical milling (MM) and spark plasma sintering (SPS) process were investigated in detail. The initial and MM powders were sintered 1.8 ks at 1173 to 1373 K by using SPS apparatus. The SPS compact of the initial and MM powders consist of FCC, μ and σ phases. The grain size of the compacts of the MM powders is fine compared with that of the initial powders. The grain sizes of each phase increase with increasing the sintered temperature. The Vickers hardness of the MM powder compacts is higher than that of the initial powder compacts. The Vicker hardness of the compacts of initial and MM powders decreases with increasing the sintered temperature. It is revealed that the hardness of CrFeCoNiMo HEA is attributed to the grain size of each phase composed of the microstructure.