Long-period stacking ordering induced ductility of nanolamellar TiAl alloy at elevated temperature
Guoming Zheng, Bin Tang, Wei Chen, Songkuan Zhao, Yizhen Xie, Xiaofei Chen, Jinshan Li, Lei Zhu
Abstract
This work reports that the plastic deformation mechanism of lamellar microstructure (LM) in Ti-43.5Al-4Nb-1Mo-0.1B (TNM) alloy transforms from stacking faults (SFs)-dominated process to long-period stacking ordering (LPSO) structures-mediated process with a slight increase in lamellar spacing (LS) (20–36 nm). Multiple LPSO bands significantly enhance the work hardening response and trigger the transformation-induced plasticity (TRIP) effect, causing a four-fold higher ductility than SF-deformed LM at 750°C without compromising yield strength (YS). This phenomenon provides novel insights into the development of high-performance TiAl alloys with extremely nano-LM (LS < 55 nm) at elevated temperatures.IMPACT STATEMENTThe development of multiple nanometer-sized LOPS bands during deformation in nanolamellar TiAl alloys can significantly improve ductility without resulting in a reduction of yield strength.