Influence of the sintering atmosphere on the tensile properties of MIM-processed Ti 45Al 5Nb 0.2B 0.2C

In this study tensile test specimens were produced by metal injection moulding (MIM) of gas-atomised TNB-V5 alloy powder with the nominal composition Ti 45Al 5Nb 0.2B 0.2C (at.%). The specimens were sintered at 1500 °C under different atmospheres. The influence of the sintering atmosphere and the sintering time on the tensile properties, the microstructure and Al-sublimation were investigated. The residual porosity of the specimens increased proportionally with the applied argon gas pressure during sintering from 0.1% for vacuum to 1.1% for 80 kPa. Nevertheless, no relationship between the sintering pressure and the mechanical properties was found and ultimate tensile strengths (UTS) between 625 and 630 MPa with plastic elongations of 0.15–0.19% at room temperature were determined.

► Ti 45Al 5Nb 0.2B 0.2C (at.%) processed by metal injection moulding (MIM).
► A residual porosity of 0.1% was achieved by sintering in vacuum.
► Sublimation of aluminium suppressed by sintering in argon of 30 kPa or more.
► UTS of 630 MPa and plastic elongations of 0.15–0.19% at room temperature.
► Low oxygen levels of sintered parts between 1140 and 1437 μg/g.