Effect Of Milling Duration On Oxide-Formation Behavior Of Oxide-Dispersion-Strengthened High-Entropy Alloys

Oxide-dispersion-strengthened high-entropy alloys were produced by hot-pressing a ball-milled mixture of Y2O3 and atomized CoCrFeMnNi powder. The effect of milling duration on grain size reduction, oxide formation behavior, and the resulting mechanical properties of the alloys was studied. Both the alloy powder size and Y2O3 particle size decreased with milling time. Moreover, the alloy powder experienced severe plastic deformation, dramatically generating crystalline defects. As a result, the grain size was reduced to similar to 16.746 nm and in-situ second phases (e.g., MnO2 and sigma phase) were formed at the defects. This increased the hardness of the alloys up to a certain level, although excessive amounts of in-situ second phases had the reverse effect.