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

Abstract

High-temperature deformation behaviors of a nonequiatomic novel AlNbTi 3 VZr 1.5 refractory high entropy alloy were studied. Hot compression tests were carried out at different temperatures ranging from 1100 to 1250 ℃ 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 °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 AlNbTi 3 VZr 1.5 RHEA during the hot compression deformation. The size and volume percentage of dynamically recrystallized grains increase as the Z parameter decreases. • The high-temperature behavior of novel AlNbTi 3 VZr 1.5 refractory high entropy alloy is investigated. • The apparent activation energy was 228.1 kJ/mol. • The best processing window is determined at 1200–1250 °C and 10–0.75–1 s −1 . • Discontinuous dynamic recrystallization along grain boundaries is the main softening mechanism of the AlNbTi 3 VZr 1.5 RHEA during the hot compression deformation.