Abstract
The effect of Mn addition on the mechanical properties of TiAl base alloys was examined by compression test for Ti-35mass%Al, Ti-36mass%Al and Ti-34.5mass%Al-1.45mass%Mn alloys in the temperature range of 296 to 1 073 K at strain rates of 10-1 to 10-4 sec-1. Mn addition to the TiAl alloy increased the proof stress and improved the deformability at both room temperature and high temperatures. The proof stress of the TiAl alloy containing Mn had the positive temperature dependence for both the as-cast and the heat-treated alloys. The reason for the positive temperature dependence of the proof stress in the as-cast alloy is different from that in the heat-treated alloys, i.e. in the former it is due to a large amount of Ti3Al phase and in the latter alloy it is due to the decrease of the Al content in TiAl phase. The as-cast alloy containing Mn deformed soundly at 1073 K at a strain rate of 10-1 sec-1 and had the compressive strain of more than 50%.
