Atomistic simulations of the deformation behavior of an Nb nanowire emb e dde d in a NiTi shape memory alloy

초록

The influence of pre-strain and temperature on the superior properties exhibited by an Nb nanowire em-bedded in a NiTi shape memory alloy (SMA) are investigated via molecular dynamics simulations. To this end, a new Nb-Ni-Ti ternary interatomic potential based on the second nearest-neighbor modified embedded-atom method (2NN MEAM) is developed and employed. The origin of the unique phenom-ena of quasi-linear elasticity, slim hysteresis, and reduction in Young's modulus observed for pre-strained nanowire-SMA composites is uncovered. The results demonstrate the importance of plastic deformation in the embedded Nb nanowires and reveal how the deformation facilitates the just-mentioned, unprece-dented phenomena. A simple and straightforwardly obtainable descriptor to correlate and monitor the Young's modulus evolution during pre-straining is proposed. Furthermore, our simulations suggest that the desired Young's modulus can be obtained for a wide range of application temperatures through ap-propriate pre-straining. (c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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