Yet the desire and pursuit for high-performance materials with high strength and toughness have never faded for scientific research and industrial applications. Originally, an attraction was paid to HEAs due to their unique single-phase structures stabilized by the high configurational entropy. On the other hand, the research on refractory HEAs with high strength and hardness is also in full swing, , ]. They have been systematically studied and evolved into several subsets, such as CoCrFeNi, CoCrNi and FeMnCoCr HEAs. Different from conventional metals and alloys, the prototypical CoCrFeNiMn HEA, also called Cantor alloy, is to be firstly discovered. In HEAs, there is no difference between the solute and solvent atoms, that is to say, multiple principal components in equimolar or near-equimolar ratios. High-entropy alloys (HEAs) and compositionally-complex alloys (CCAs) have drawn tremendous attentions for their interesting responses, such as superior mechanical properties, high-temperature stability and outstanding fatigue, fracture and wear resistances, ,, ,, ,, ,, ,, , ]. This study sheds lights on the mechanical performance superiority from heterogeneous HEAs under dynamic tension and might open new insights for developing high-performance HEAs to resist dynamic impacts. Moreover, a typical Johnson-Cook model was employed to predict the dynamic-flow behavior.

In contrast, under quasi-static tension, only dislocation slip dominates, accompanied by dislocation entanglement and massive pile-ups. Besides, short range order may seriously hinder the dislocation movement, especially when the thermal activation of dislocations gradually fails at high strain rates, which limit the dislocation slip to a smaller scale and result in deformed sub-grains. Deformation-induced twinning further improves the strain-hardening ability of the alloy.

Upon dynamic tension, the simultaneous enhancements of both strength and ductility are attributed to the joint activation of multiple strengthening mechanisms. The strain rate sensitivity under quasi-static tension is 0.0172, in contrast to 0.3978 under dynamic deformation. Meanwhile, the elongation is slightly improved as the strain rate rises. The yield strength and ultimate tensile strength are increased from 398 MPa to 679 MPa at 10 −4 s −1 to 743 MPa and 1412 MPa at 3000 s −1, respectively. A heterogeneous structure composed of a phase distribution and grain size is formed. This alloy consists of a tetragonal σ phase and minority M 23C 6 carbides embedded in the continuous FCC matrix after thermomechanical treatments. Face-centered-cubic (FCC) Fe 40Mn 20Cr 20Ni 20 high-entropy alloys (HEAs) with a weigh of 50 Kg were fabricated by industrialized vacuum-induction melting.

Dynamic tension pdf