Influence of the vacuum hot pressing process on the microstructure, mechanical properties, and material characteristics of CrCoNiTa3 alloys

Abstract

This research fabricates CrCoNiTa3 alloys using the vacuum hot pressing process, where micron grade chromium (6 μm), cobalt (3 μm), nickel (3 μm) and tantalum (25 μm) powders are mixed by means of ball milling. The experiments utilize various hot pressing temperatures (1000, 1050, 1100, and 1150 °C) and hot pressing pressures (20, 35 and 50 MPa) to determine the optimal hot pressing parameters for CrCoNiTa3 alloys, while simultaneously investigating the differences in microstructures and material characteristics. The results show that the optimal hot pressing parameters of this alloy were 1100 °C at 20 MPa for 1 h. The sintering density was enhanced to 8.34 g cm−3, and the hardness and transverse rupture strength (TRS) reached 72.9 HRA and 2266.1 MPa, respectively. Meanwhile, the electrical conductivity was 1.46 × 103 S cm−1 and the polarization resistance was 1309.1 Ω cm2. Furthermore, the EBSD results confirm that the FCC solid solution and twin of the CrCoNiTa3 crystalline structure, and no preferred grain orientation was found.