Shape memory metamaterials with tunable thermo-mechanical response via hetero-epitaxial integration: A molecular dynamics study

KG Vishnu and A Strachan, JOURNAL OF APPLIED PHYSICS, 113, 103503 (2013).

DOI: 10.1063/1.4794819

We show that nanoscale epitaxial superlattices (SLs) can be used to engineer the energy landscape that governs the martensitic transformation in shape memory alloys and tune their thermo-mechanical response. We demonstrate the approach using large-scale molecular dynamics simulations of a SL material consisting of alternate layers of a shape memory Ni-rich NiAl alloy and NiAl B2 alloy. The non-martensitic NiAl alloy was chosen to reduce the energy barrier that separates the martensite and austenite phases of the SL and its incorporation leads to a reduction in the thermal hysteresis of the transition. This is a desirable feature in applications involving actuation and our approach represents a generally applicable and powerful avenue to engineer desired behavior in mechanically active materials. (C) 2013 American Institute of Physics.

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