Effects of deformation–induced BCC martensitic transformation and twinning on impact toughness and dynamic tensile response in metastable VCrFeCoNi high–entropy alloy

Effects of cryogenic temperature on tensile and impact properties in a medium-entropy VCoNi alloy

“…This behavior is different from the temperature dependence of the impact or fracture toughness of previously reported fcc-based HEAs or MEAs, such as CrMnFeCoNi [ 10 , 35 ], Cr-CoNi [36] , CrFeCoNi [37] , and VCrFeCoNi [ 38 , 39 ]. The toughness of these alloys remains or even increases as the testing temperature decreases, which is known to be due to the transition of the deformation mechanism from slip to deformation twinning, the increased nano-twinning activity [ 10 , 35-37 ], or the formation of deformation-induced martensite [38] during plastic deformation. The present VCoNi alloy, in contrast, deformed by the planar glide of dislocations and subsequent formation of dislocation substructure, and not by transformation-induced plasticity (TRIP) or twinning-induced plasticity (TWIP).…”

High strength and ductility in partially recrystallized Fe40Mn20Cr20Ni20 high-entropy alloys at cryogenic temperature

“…The low-temperature yield strength and elongation of the alloy in this study are compared with other FCC structural alloys, as shown in Figure 9A. Clearly, the present HEA has better low-temperature mechanical properties than those of other alloys, for example, Al alloys [30] , high Mn steels [31] , Ni-based steels [32,33] , transformation-induced plasticity steels [34] and other HEAs [4,[23][24][25][35][36][37][38][39][40][41][42][43] . It is particularly obvious that the yield strength and UTS are the highest, with values of 1080 and 1150 MPa, annealed at 600 °C, respectively, with a loss of ductility.…”

“…Figure 9B presents the cost and elongation of samples with different annealing treatments of the current HEA at 77 K, with the results of many recently developed structural alloys also included. Compared with traditional Al alloys [44] , Mg alloys [35,45] , Ni-based steels [46] , Fe-Mn steels [47,48] , high Mn steels [49,50] , CrMn-based alloys [51] , 304 steels and even most HEAs [4,36,37] , although the strength is slightly lower than that of Ti alloys, the HEA studied has a significant cost advantage. Since there is no expensive Co element, but there is a very economical Fe element, the current alloy is more economical than other HEAs.…”

A brief review of metastable high-entropy alloys with transformation-induced plasticity

“…Interestingly, SFE is found to have a weak dependence on the number of elements in the alloy system. Meanwhile, influence of deformation temperature [45,75,76], local chemical fluctuations [30,53], and magnetic state (ferromagnetic and paramagnetic) [64,77] can also affect SFE to a certain extent. For example, with decreasing deformation temperature, deformation twinning, and martensitic phase transformation occur successively, which means that there is a positive dependence between the temperature and SFE of alloys.…”