Low-Angle Twist Phase Boundary Mediated Plasticity in a High-Strength Ti78Fe22 Alloy

Ti-Fe alloys with improved strength-plasticity trade-off are promising low-cost engineering materials. In this work, we report the attainment of an A2 + B2-type superalloy microstructure featuring a low-angle twist boundary in an aged Ti78Fe22 alloy. The alloy delivered a high yield strength of 1590 ± 5 MPa and an exceedingly large plastic strain of 40 ± 2% at room temperature. Upon deformation, the low-angle twist boundary acted as the dislocation source for continued dislocation emission and regulated cross-slip. The massive production of dense parallel slips accommodates the large plastic strain under a high external stress.