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High-activity spherical TaNbTiZr refractory high-entropy alloy (REHA) powders were successfully prepared by electrode induction melting gas atomization (EIGA) and plasma rotating electrode process (PREP) methods. Both the EIGAed and PREPed TaNbTiZr RHEA powders have a single-phase body-centered cubic (BCC) structure and low oxygen content. Compared with the EIGAed powders, the PREPed powders exhibit higher sphericity and smoother surface, but larger particle size. The average particle sizes of the EIGAed and PREPed powders are 51.8 and 65.9 μm, respectively. In addition, both the coarse EIGAed and PREPed powders have dendritic structure, and the dendrite size of the EIGAed powders is larger than that of the PREPed powders. Theoretical calculation indicates that the cooling rate of the PREPed powders is one order of magnitude higher than that of the EIGAed powders during the solidification process, and the dendritic structure has more time to grow during EIGA, which is the main reason for the coarser dendrite size of the EIGAed powders.

FeCrNi medium entropy alloy (MEA) is a promising structural material due to its outstanding mechanical properties and corrosion resistance. However, study on the high-temperature tribological behaviors of FeCrNi MEA is still scarce. This work investigates the tribological performances of the FeCrNi MEA against Si3N4 balls over typical operating temperatures from 25 to 800 °C. The FeCrNi MEA exhibits excellent wear resistance at an intermediate temperature of 600 °C. The microstructure characterization of the wear tracks reveals a transition in the wear mechanism from abrasive wear at 25 °C to oxidative-delamination wear at 600 °C. The improved tribological performances are mainly attributed to the high Cr content, which promotes the formation of the compact oxide layer and the precipitation of the hard sigma (σ) phase.