For the first time, a powder of refractory body-centered cubic (bcc) HfTaTiNbZr-based high-entropy alloy (RHEA) was prepared by short-term (90 min) high-energy ball milling (HEBM) followed by spark plasma sintering (SPS) at 1300 °C for 10 min and the resultant bulk material was characterized by XRD and SEM/EDX. The material showed ultra-high Vickers hardness (10.7 GPa) and a density of 9.87 ± 0.18 g/cm³ (98.7%). Our alloy was found to consist of HfZrTiTaNb-based solid solution with bcc structure as a main phase, a hexagonal closest packed (hcp) Hf/Zr-based solid solution, and Me₂Fe phases (Me = Hf, Zr) as minor admixtures. Principal elements of the HEA phase were uniformly distributed over the bulk of HfTaTiNbZr-based alloy. Similar alloys synthesized without milling or in the case of low-energy ball milling (LEBM, 10 h) consisted of a bcc HEA and a Hf/Zr-rich hcp solid solution; in this case, the Vickers hardness of such alloys was found to have a value of 6.4 GPa and 5.8 GPa, respectively.

Thermal explosion (ignition) of various Ni-Al samples—such as powder blends, rolled and magnetron sputtered films, compacts of mechanically activated and non-activated mixtures—was explored with special emphasis on the role of mechanical activation. The critical ignition temperature (T _c) was found to diminish from 650°C for starting (non-activated) Ni-Al mixtures down to 280°C for properly activated samples. For the thin films of alternating Ni and Al layers prepared by magnetron sputtering, T _c turned out to be as low as 230°C.

Nanostructured powders of pseudoalloys of immiscible Cu and Mo metals are prepared by highenergy ball milling (HEBM). Mechanical alloying in an Activator-2S planetary ball mill for 60 min provides a uniform distribution of refractory Mo particles in a moldable Cu matrix on submicron and nanoscopic levels. Nanostructured Cu–Mo powders are consolidated by spark plasma sintering (SPS) in a temperature range of 700–950°C at a pressure of 50 MPa for 10 min. The effect of preparation conditions on the microstructure, crystal structure, and properties (density, hardness, electric resistivity) of the nanostructured Cu–Mo pseudoalloys is studied. It is shown that a combination of HEBM and SPS provides the formation of a high-density (97%) nanostructured consolidated Cu–Mo composite with a hardness of 3.68–3.88 GPa and an electric resistivity of 6.1–6.2 μΩ cm; these parameters made the composite promising for use as an electric-contact material.

The results of the investigation into the formation of amorphous structures in the Cu–Ti system and their subsequent crystallization under the effect of high-energy ball milling (HEBM) are...