Effects of the Microstructure and Strengthening Mechanisms of Mo2C Powders Being Added to Ti-8Nb-4Co Alloy Via the Vacuum Sintering Process

Abstract

This study utilizes Ti-8nb-4Co alloys added to different proportions of Mo 2 C powders (1, 3, and 5 mass%) by the vacuum sintering process of powder metallurgy and simultaneously vacuum sinters the alloys at 1240, 1270, 1300, and 1330°C for 1 h, respectively. The experimental results indicate that when 3 mass% Mo 2 C powders were added to the Ti-8nb-4Co alloys, the specimens possessed the optimal mechanical properties after sintering at 1300°C for 1 h. The relative density was 98.02%, and the hardness and TRS were enhanced to 69.6 hRa and 1816.7 MPa, respectively. in addition, the microstructure of vacuum sintered Ti-8nb-4Co-3Mo 2 C alloys has both α and β-phase structures, as well as TiC precipitates. EBSD results confirm that the Mo 2 C in situ produced TiC during the sintering process and was uniformly dispersed in the grain boundary. Moreover, the reduced molybdenum atom acted as a β-phase stabilizing element and solid-solution in the titanium matrix.