Microstructural origin of ultrahigh damping capacity in Ni50.8Ti49.2 alloy containing nanodomains induced by insufficient annealing and low-temperature aging

We report a Ni50.8Ti49.2 alloy that exhibits an ultrahigh damping capacity with an internal friction value of ~ 0.35 (tan δ) at low frequencies in a wide temperature range. This alloy undergoes low-temperature aging after insufficient annealing from a severely deformed state (~90% cold work). Via phase transformation analyses and microstructure characterization, we demonstrate that this high broad internal friction plateau originates from...