Tailoring damping properties by electron irradiation in Ni-Mn-Ga shape memory alloys in a wide high-temperature range

Abstract Damping devices need to maintain a high internal friction value in a wide high-temperature range in an aviation environment. Damping behavior is sensitive to defects including vacancies, interstitials, and dislocations. Electron irradiation is an effective method to introduce defects into materials to tailor the damping properties. The relaxation internal friction peak value increases first and then decreases with the increase of irradiation dose in Ni54Mn25Ga21 alloy. The peak value increases from 0.04 to 0.055 by 37.5% after irradiated by 1.2 MeV electrons at 2 × 1017 e/cm2. It derives from the effect of dislocations on the interaction between interstitials and twin boundaries. The high isothermal internal friction remains stable with a large working temperature range of 160 ℃ from 50 ℃ to 210 ℃. This research provides a new method to obtain high damping Ni54Mn25Ga21 alloy with a wide high-temperature range.