Deformation-induced homogenization of the multi-phase senary high-entropy alloy MoNbTaTiVZr processed by high-pressure torsion

Microstructure Evolution and Mechanical Properties of AlCoCrFeNi2.1 Eutectic High-Entropy Alloys Processed by High-Pressure Torsion

“…The microhardness reached the first saturation state at an equivalent strain of approximately 10 before gradually rising to 500 HV. Subsequently, the microhardness steadily increased to 550 HV, reaching a second saturation point at an equivalent strain of around 40, which was consistent with the studies of many scholars [22,24,25,33,37,[41][42][43].…”

“…The variations in microhardness with equivalent strain at different HPT revolutions are presented in Figure 5b. With the increase in equivalent strain, two saturation stages were observed during the process of microhardness enhancement, which was in line with the report of Duan et al [25]. It has been suggested by Edalati et al [22] that the saturation state arose from the equilibrium between defect generation and annihilation through dynamic recovery, dynamic recrystallization, and grain boundary migration.…”

“…As displa in Figure 5d,e, the microhardness rapidly increased to 475 HV when the equivalent st was low. attributed to the required shear strain for shear deformation during HPT, as ported [25]. The microhardness reached the first saturation state at an equivalent strai approximately 10 before gradually rising to 500 HV.…”

“…Additionally, Liu et al administered a single-turn HPT treatment to AlCrFe 2 Ni 2 HEAs, inducing transformation from a biphasic structure comprising BCC and FCC phases to a singular FCC phase structure, with ensuing room temperature tensile tests indicating heightened hardness and strength but diminished elongation (about 33%) [ 24 ]. Duan et al showcased MoNbTaTiVZr dual-phase HEAs via HPT up to 40 turns, noting enhanced microhardness and more uniform elemental distribution [ 25 ]. Through dissecting the mechanism behind microhardness augmentation under varying strains, it was hypothesized that lower strain-induced hardness escalation primarily stemmed from heightened dislocation density and grain refinement, while a sharp rise in hardness under higher strains was predominantly attributed to ultra-fine crystal microstructure formation.…”