Enhancement of room-temperature mechanical properties of TiAl alloy by trace addition of C

Abstract

Lightweight and high-temperature-resistant γ-TiAl based alloys have attracted considerable research attention for application in aerospace and automotive engines. For TiAl alloys, C alloying is usually beneficial for improving the high-temperature mechanical properties, while deteriorates the room-temperature (RT) mechanical properties, particularly the plasticity. This study demonstrates that trace C alloying can significantly improve the RT mechanical properties of a cast Ti–46Al–6Nb alloy. The initiation and propagation of microscopic cracks during three-point bending with and without C microalloying were analyzed. A comprehensive effect that involves segregation, phase content, hardness, lamellar spacing, and lamellar interface improvement is proposed for the simultaneous enhancement of the strength and plasticity with trace C addition. This study offers an accurate and feasible strategy to utilize the solid-solution strengthening of interstitial C in TiAl alloys.