The heterogeneity of mechanical response in gradient-structured CoCrNi alloy deformed upon quasi-static and dynamic compression

Dynamic mechanical behavior and deformation mechanisms of gradient-structured (GS) materials represent a novel area of research, offering new opportunities for their application in dynamic impact scenarios. In this study, GS-CoCrNi medium-entropy alloys were synthesized, and compression experiments were conducted over a wide range of strain rates (from 10⁻⁴ /s to 10³ /s). The significantly different strain rate sensitivities of the strengths observed at the edge and center regions result in markedly distinct macroscopic mechanical behaviors. Under quasi-static conditions, an upward concavity in the hardness increment (strength increment) is noted, whereas in the dynamic state, an opposite upward convexity is observed.