INVESTIGATION OF THE MICROSTRUCTURE AND STRENGTHENING MECHANISMS OF Ti-6Cu-8Nb-xCr₃C₂ ALLOY THROUGH VACUUM SINTERING PROCESS

This study mixes four different powders to produce Ti-6Cu-8Nb-xCr₃C₂ (x = 1, 3, and 5 mass%) alloys in three different proportions. The experimental results reveal that when 5 mass% Cr₃C₂ was added to the Ti-6Cu-8Nb alloys, the specimen possessed optimal mechanical properties after sintering at 1275°C for 1 h. The relative density reached 98.23%, hardness was enhanced to 67.8 HRA, and the transverse rupture strength (TRS) increased to 1821.2 MPa, respectively. The EBSD results show that the added Cr₃C₂ in situ decomposed into TiC and NbC during the sintering process, and the generated intermetallic compounds (Ti₂Cu) were evenly dispersed in the Ti matrix. Furthermore, the reduced Cr atom acts as a β-phase stabilizing element and solid-solution in the Ti matrix. Consequently, the main strengthening mechanisms of the Ti-6Cu-8Nb-xCr₃C₂ alloys include dispersion strengthening, solid-solution strengthening, and precipitation hardening.