Microstructure Refinement of a Transformation-Induced Plasticity High-Entropy Alloy

• Main Authors: Hai-long Yi, Daixiu Wei, Ren-yi Xie, Yi-fan Zhang, Hidemi Kato
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Materials
• Subjects: high-entropy alloy; hot deformation; dynamic recrystallization; constitutive equation; microstructure
• Online Access: https://www.mdpi.com/1996-1944/14/5/1196

High-entropy alloys (HEAs) have attracted extensive interest due to their unprecedented structure and mechanical performance. We recently proposed a series of novel corich twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) HEAs with superior tensile properties at room temperature; however, the hot deformation behavior has not been reported. Here, we investigated the dynamic recrystallization behavior and grain refinement of a representative TRIP-HEA, compressed at temperatures of 1123–1273 K with strain rates of 0.1–0.001 s⁻¹. We characterized the impact of the temperature and strain rate on the grain structure evolution. A constitutive equation was constructed to reveal the correlations between the flow stress, strain rate, temperature, and strain. The apparent activation energy was estimated to be ~385.7 kJ/mol. The discontinuous dynamic recrystallization played an important role in the grain refinement, particularly at a relatively higher temperature and a lower strain rate, and the volume fraction and morphology of the recrystallized grains exhibited a strong dependency on the Zener–Hollomon parameter. The study provides guidelines for the grain refinement of HEAs through thermomechanical processing.