High-temperature deformation behavior and processing maps of a novel AlNbTi3VZr1.5 refractory high entropy alloy

High-temperature deformation behaviors of a nonequiatomic novel AlNbTi3VZr1.5 refractory high entropy alloy were studied. Hot compression tests were carried out at different temperatures ranging from 1100 to 1250 celcius and various strain rates from 0.001 to 1 s(-1). The true stress-true strain curves indicated obvious sharp drops in the flow stress after reaching peak stress. This may be caused by either dislocation unlocking from a substitutional solute atmosphere or destroying short-range ordered structures. Flow stress analysis was investigated by introducing the Arrhenius constitutive relation. The apparent activation energy (Q) for high-temperature deformation was calculated to be 228.1 kJ/mol. The processing maps show that the best processing window was determined at 1200-1250 degrees C and 10-0.75 to 1 s(-1). Detailed microstructure evolution characterization with EBSD analysis shows that the occurrence of discontinuous dynamic recrystallization along grain boundaries is the main softening mechanism of the AlNbTi3VZr1.5 RHEA during the hot compression deformation. The size and volume percentage of dynamically recrystallized grains increase as the Z parameter decreases. (c) 2022 Published by Elsevier B.V.