Effect of Mn content on mechanical properties and corrosion resistance of Ti–8Mo-xMn alloys through the vacuum sintering process

Abstract

This study mixed various powders (Ti, Mo, and Mn) according to the nominal Ti–8Mo-xMn (x = 1, 3, 5 wt%) composition, and vacuum sintered the compacts of the Ti–Mo–Mn alloys at 1220 °C, 1240 °C, 1260 °C, and 1280 °C for 1 h. The experimental results show that the Ti–8Mo–3Mn alloys sintered at 1260 °C had better comprehensive properties, with a relative density of 96.71 ± 0.14 %, transverse rupture strength (TRS) of 1624.4 ± 29.2 MPa, and hardness of 67.8 ± 0.4 HRA. However, due to the microstructure evolution and increased amount of Mn in the Ti–8Mo-xMn alloys, the TRS shows a significant increase. Consequently, the suitable Mn content of the Ti–8Mo–3Mn alloys, which proves advantageous to the TRS, results from the uniformly distributed lamellar-like Widmanstätten microstructure and the basket-net microstructure. Moreover, the Ti–8Mo-xMn alloy does not have intermetallic compounds, and only consists of two phases, α-Ti and β-Ti. Furthermore, the sintered Ti–8Mo–3Mn alloys possess the suitable corrosion current (Icorr was 4.56 × 10−5 A cm−2) and polarization resistance (Rcorr was 569.76 Ω cm2) in 0.1 N H2SO4 solutions, which confirms that sintered Ti–8Mo–3Mn alloys can improve mechanical properties.