Snoek-type damping performance in strong and ductile high-entropy alloys

Noise and mechanical vibrations not only cause damage to devices, but also present major public health hazards. High-damping alloys that eliminate noise and mechanical vibrations are therefore required. Yet, low operating temperatures and insufficient strength/ductility ratios in currently available high-damping alloys limit their applicability. Using the concept of high-entropy alloy (HEA), we present a class of high-damping materials. The design is based on refractory HEAs, solid-solutions doped with either 2.0 atomic % oxygen or nitrogen, (Ta0.5Nb0.5HfZrTi)(98)O-2 and (Ta0.5Nb0.5HfZrTi)(98)N-2. Via Snoek relaxation and ordered interstitial complexes mediated strain hardening, the damping capacity of these HEAs is as high as 0.030, and the damping peak reaches up to 800 K. The model HEAs also exhibit a high tensile yield strength of similar to 1400 MPa combined with a large ductility of similar to 20%. The high-temperature damping properties, together with superb mechanical properties make these HEAs attractive for applications where noise and vibrations must be reduced.