Effect of carbon on high temperature compressive and creep properties of β-stabilized TiAl alloy
(State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: Carbon is an important alloying element in improving high temperature mechanical properties of various metallic materials. The effects of carbon on high temperature mechanical properties of a β-stabilized Ti-45Al-3Fe-2Mo (molar fraction, %) alloy were studied through compressive and creep tests. The results show that the carbon addition (0.5%, molar fraction) obviously enhances the high temperature compressive strength and creep resistance of the β-stabilized Ti-45Al-3Fe-2Mo alloy. A lot of nano-scaled Ti3AlC carbides precipitate in the β-stabilized alloy and these carbides pin the dislocations, and greatly increase the high temperature properties. At the same time, the carbon addition decreases the amount of b phase, refines the lamellar spacing, and causes solution strengthening, which also contribute to the improvement of the high temperature properties.
Key words: TiAl alloy; carbon; precipitation; high temperature compression; high temperature creep