Microstructure, deformation behavior, and dynamic recrystallization kinetics of FeNiMnCu-based high entropy alloys prepared by mechanical alloying and spark plasma sintering

Abstract

In the present research, FeNiMnCuX (X: Co, Cr, Mo, Ti, W) high entropy alloys (HEAs) were successfully fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). SPS transformed the base and Co-containing alloys into FCC structures, Cr- containing alloys changed into a mix of FCC and BCC structures, while other alloys formed a combination of FCC/BCC structure and an intermetallic compound. The base alloy and alloys with Co, and Cr additions exhibited plastic deformation in cold compression tests, whereas other alloys exhibited brittle behavior. During hot compression tests, dynamic recrystallization occurred with a peak in flow stress followed by a gradual decrease to a steady state stress in alloys with Co, Mo, Ti and W additions. The highest peak stresses were observed at 800 °C for Ti- and W- containing alloys. The dynamic recrystallization and fractional softening kinetics are explained by the Avrami kinetic model. An Avrami exponent around 1 was obtained based on the kinetics of dynamic recrystallization for the alloys doped with Co, Mo, Ti, and W.