Shaped charge jet formation and penetration to steel target of FeNiCoCr high-entropy alloy liners

High-entropy alloy (HEA), characterized by excellent mechanical properties such as high density, ductility, and sound velocity, has demonstrated potential application prospects in the shaped charge liner. This study mainly conducted a comparative analysis of FeNiCoCr HEA and oxygen-free high conductance (OFHC) copper, focusing on their mechanical characteristics, shaped charge jet formation and penetration characteristic into steel targets. The results demonstrated that FeNiCoCr HEA exhibits excellent comprehensive and ductility, which underscoring its suitability for potential materials of shaped charge liner. The shaped charge jet formation from X-ray Flash observation indicated that FeNiCoCr HEA liner jet shows typical morphology which as the traditional OFHC copper jets, although it exhibits discernible radial expansion during formation process. For the penetration ability, the penetration hole of FeNiCoCr HEA jet shows a larger diameter, but smaller depth than that of OFHC copper jets. Meanwhile, the penetration hole in the target were characterized using optical microscopy (OM) and scanning electron microscopy (SEM) to further understand the interaction characteristics between residual jet and target. Our findings revealed that, the difference of OM results in the target gray area suggested that the impact energy of FeNiCoCr HEA jet was less than that of the OFHC copper jet, while the element Fe diffusion and intense interaction between the HEA residual jet and penetration hole wall explained the hole morphology and the diffusion behavior of residual HEA jet provided support for the currently debated sluggish diffusion effect. These findings provided new insights into the engineering applications of HEAs under extreme conditions.