Investigation of the vacuum hot pressing process on the mechanical properties,microstructures and material characteristics of Ni–35Mo–15Cr alloys

Abstract

This study fabricated Ni–35Mo–15Cr alloys by the vacuum hot pressing technique. The experiments utilised various hot pressing temperatures (1050°C, 1100°C, 1150°C, and 1200°C) and pressures (20, 35, and 50 MPa) to determine the optimal parameters for Ni–35Mo–15Cr alloys. The experimental result showed that the optimal hot pressing parameters of this alloy were 1150°C at 35 MPa for 1 h. Among them, the sintering density reached 8.92 g·cm⁻³, and the hardness and TRS increased to 77.1 HRA and 1218.2 MPa, respectively; while, the electrical conductivity was 7.08 × 10³ S cm⁻¹ and the polarisation resistance was 294.65 Ω·cm². Furthermore, the TEM observation identified the HCP structures of the Mo₂C that precipitated in the Ni–35Mo–15Cr alloys, and the [02 1] and [01 2] crystal axis of Mo₂C can be found. Overall, the properties of Ni–35Mo–15Cr alloys were effectively improved through the hot pressing process.