The effect of precipitates on the superelastic response of [1 0 0] oriented FeMnAlNi single crystals under compression

FeMnAlNi shape memory alloys were recently discovered to have a small temperature dependence of the superelastic critical stress in a large superelastic temperature window from −196 °C to 240 °C. In this work, we investigated the effect of B2 nanoprecipitates on the superelastic characteristics of [1 0 0] oriented Fe43.5Mn34Al15Ni7.5 single crystals under compression, and found that the size, volume fraction and composition of precipitates strongly influence the transformation temperature, superelastic strain, critical stress for stress-induced martensitic transformation and stress hysteresis of the single crystals. The single crystals aged at 200 °C for 3 h show 7.2% superelastic strain with the precipitate size of about 6–10 nm. Longer aging times or higher aging temperature reduces superelastic recovery due to the coarsening of the precipitates.

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