The ultrahigh damping capacity in a friction stir-processed Cu-Al-Ni high-temperature shape memory alloy

Friction stir-processed (FSPed) Cu-13.2Al-4Ni (wt.%) high-temperature shape memory alloy exhibited ultrahigh internal friction of ≈0.41 at low frequencies. The ultrahigh-damping capacity was attributed to the grain refinement and the textured structure. The refined grain boundaries made an enhanced energy dissipation. Simultaneously, a strong {128} textured martensite with 'single-pair' morphology in the present alloy after FSP also improved the damping capacity due to the introduction of numerous interfaces with better interface mobility. The results are expected to further expand the capacity for designing damping material.