A coherent atomic configuration model of Ni4Ti3 and its application to atomic-level characterization of precipitation induced strain fields in NiTi alloy

This paper proposes an innovative and practical modeling method to create a coherent atomic configuration of NiTi austenite with lenticular Ni4Ti3 based on molecular dynamics (MD) approach. The initial configuration of Ni4Ti3 is created by expanding lattice constants and then relaxed at specified temperature coupled with energy minimization scheme to optimize the configuration while maintaining coherence with B2 austenite. Ni4Ti3 precipitates in parallel, step-like and edge-to-edge models generate different strain fields by MD simulations; strain fields in the interior of Ni4Ti3 precipitates and at precipitate-matrix interfaces are more consistent with experiments in comparison to that yielded by the Eshelby solution (ES).