Hot deformation behavior of Ni₆₁Fe₁₀Cr₁₀Al₁₇Mo₂ high-entropy alloy with hierarchical structure

The Ni₆₁Fe₁₀Cr₁₀Al₁₇Mo₂ high-entropy alloys (HEAs) with low density have been developed with great potentials for applications. The forging process is one of the important methods for fabricating components. Accordingly, the study of the deformation behavior of HEAs is the essence in the processing and molding of this material for using in industry. Moreover, there are multiple phases with hierarchical structures in the as-cast Ni₆₁Fe₁₀Cr₁₀Al₁₇Mo₂ alloys, with the face-centered cubic (FCC) phase as the matrix phase accompanied with hard body-centered cubic (BCC) B2 phase. Here, the hot deformation behaviors of the homogenized Ni₆₁Fe₁₀Cr₁₀Al₁₇Mo₂ alloy were investigated at strain rates ranging from 0.001 to 1.0 s⁻¹ and temperatures ranging from 1000 to 1200 °C via isothermal compression tests. The true stress-strain curves were used to reveal the relationship between the flow stress and the deformation temperature and strain rate. The constitutive equations describing the correlations between the flow stress and hot compression parameters were constructed. At the same time, the dynamic material model and instability criterion were used to plot the hot processing map. Furthermore, the deformed microstructures and the dynamic recrystallization of alloy were investigated. Combined with the processing map, the optimal processing route is obtained.