Fig. 1. (a) Gaseous-detonation driven ballistic range DBR30 device and (b) experimental layout for the penetration tests.

Fig. 2. (a) XRD pattern of the as-cast TiZrHfTa0.7W0.3 sample, (b) grain size distribution with the region in (c), (c) EBSD IPF map, (d) phase map.

Fig. 3. (a) BSE image near the grain boundary and (b) SEM-EDS element distribution of the red dashed region in (a).

Fig. 4. (a) Selected area of the FIB-TEM sample and corresponding SAED patterns of the precipitates and the matrix; (b) TEM-EDS maps of the red region in (a) and the corresponding fast Fourier transform patterns of the BCC1 and HCP matrix.

Fig. 5. Compressive mechanical properties at various strain rates of the TiZrHfTa0.7W0.3 HEA: (a) engineering stress-strain compression curves; (b) yield strength (YS), ultimate strength (US), and fracture strain (FS); (c) corresponding strain hardening rates.

Fig. 6. High-speed photographs during Hopkinson bar impact tests ($\dot{\mathcal{\varepsilon}}$= 4200 s?1), where the sample failed at 50 μs, and metal combustion was observed along the fractured surface.

Fig. 7. (a) Remnant fracture surface at 4200 s?1. Red circles mark a large number of molten particles, and the two red lines (denoted as b and c) in the yellow region are for the EDS line scanning; (b, c) corresponding EDS line profiles for lines b and c in (a), respectively.

Fig. 8. XPS spectra of Ti, Zr, Hf, Ta, and W elements on the fracture surface at 4200 s?1 and the percentage of metals and metal oxides.

Fig. 9. High-speed video frames of the penetration process of TiZrHfTa0.7W0.3 HEA projectiles: (a) with optical filters and background light source, (b) without optical filters and background light source.

Fig. 10. (a) Cross-section of the target plate with YL10.2 alloys (left), HEA in this study (middle), and 18Ni stainless steel (right) cylindrical projectiles; (b) hole diameter vs. depth diagram, and the inset is the volume of penetration channel; (c) relationship of kinetic energy with P/L; (d) relationship of kinetic energy with D*/Dpro.