Microstructure evolution and plastic deformation behavior of DR-B2/ID-FCC phase lightweight high entropy alloy during improving thermal processing properties

Abstract

This paper comprehensively benchmarks the aero-engine hot-end component material GH4169/Inconel718. A nickel-based lightweight high entropy alloy (HEA) with a nearly equimolar distribution of DR-B2 + ID-FCC was prepared using a multi-element non-equimolar design. And carry out hot compression experiments using XRD, TEM, and EBSD detection methods to study energy dissipation and redistribution (η value) as the starting point. The results indicate that heterostructure is beneficial for expanding the thermal processing window, and a machinable zone (900 °C/0.32 s⁻¹) also appears in the low η value interval. In the medium/high η value interval, the alloy has more machinable ranges due to the contribution of the dynamic response behavior of heterostructure and the evolution behavior of dislocations. The ID-FCC phase exhibits discontinuous dynamic recrystallization (DDRX), mainly forming {001} < 0$\overline{1}$0 > Cube texture. The DR-B2 phase is continuous dynamic recrystallization (CDRX) with no apparent preference for texture orientation. The volume fraction of FCC phase recrystallization (X_rec) is higher than that of the B2 phase (X_rec-FCC: X_rec-B2 = 1.05–2.3), making it more prone to recrystallization. Meanwhile, the FCC/B2 phase deformation mechanism is mainly a dislocation climb creep mechanism (n₁ = 4.96). These research results guide designing lightweight heterostructure HEA with good thermal processing performance.