| TiAl intermetallic compounds are regarded as one of the most feasible future elevated temperature structural materials, because of their high elevated temperature strength and oxidation resistance. However, it has been pointed out that they are difficult to fabricate due to their poor ductility at room temperature, which restricts their applications. In this study, attempts to improve the room temperature ductility of TiAl intermetallic compounds were made via the addition of Mn and designing heat treatments, which can refine grain size, shorten slip length and control microstructure and phase constitution. Maximum strain was obstained at the composition of Ti-47.6Al-2.7Mn(at.%) heat created at 1623 K for 30 hours. This can be rationalized by the fact that the addition of Mn tends to lower volume fraction of α₂, promote formation of γ phase containing twins, change axial ratio (c/a), refine grain size and shape lamellar morphology. Peak hardness value was obtained with the heat treatment at 1623 K for 30 hours. This increased hardness might be explained in terms of the increased volume of the α₂ phase and decreasing grain size by the addition of Mn. |
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