Synergistic damping effect mechanism of magneto-mechanical hysteresis and dislocations energy dissipation in FeMnCrCo high entropy alloys

The Fe65-xMn20Cr15Cox (x = 0, 5, 10, 15) high entropy alloys (HEAs) were prepared by mechanical alloying (MA) and spark plasma sintering (SPS). The effects of the configurational entropy on the microstructure, magnetic properties, and damping behaviors were investigated in this paper. As the Co content increased, the configurational entropy of the HEAs was increased from 0.88R to 1.23R, the magnetology performance was reduced significantly, but the peak of internal friction (IF) Q-1 increased monotonously. The maximum internal friction (IF) Q-1max achieved 0.073 when 15 at% Co element was added. With the configurational entropy increasing, in addition to the ferromagnetic damping mechanism, the dislocation damping mechanism was introduced in the HEAs. The synergistic effect of magneto-mechanical hysteresis and dislocation energy dissipation ensured the FeMnCrCo HEAs maintained high damping performance in a wide strain amplitude. Through the regulation of the microstructure, the possibility of application of the damping alloy under extreme conditions can be expanded.