NiTi shape memory alloys under nanoindentation with different atomic compositions

ABSTRACT

Molecular dynamics simulations were conducted to explore nanoindentation-induced martensitic transformation in NiTi shape memory alloys. Three atomic compositions and two indenter sizes were considered. During loading, the B2 structure underwent martensitic transformation to the B19' structure, accompanied by atomic rearrangement in the form of bands. After unloading, a portion of the B19' phase underwent reversible transformation, while the remainder remained in the form of bands, resulting in residual strain. This effect was accentuated by the more localised deformation promoted by the smaller indenter. The influence of atomic composition was observed not to play a key role in the mechanical and structural properties, contrary to previous reports on tension and compression tests. Our findings shed light on the intricate interplay of factors influencing the mechanical performance of NiTi shape memory alloys at the atomic scale, providing crucial insights for the design and understanding of such materials.

KEYWORDS:

• Shape memory alloys
• atomic composition
• indentation
• molecular dynamics

Disclosure statement

No potential conflict of interest was reported by the author.

CRediT authorship contribution statement

N. Amigo: Conceptualization, Software, Investigation, Methodology, Visualisation, Formal analysis, Writing – review & editing – original draft, Resources.

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared at this time due to technical or time limitations.

Additional information

Funding

Project supported by the Competition for Research Regular Projects, year 2023, code LPR23-05, Universidad Tecnológica Metropolitana. Powered@NLHPC: This research was partially supported by the supercomputing infrastructure of the NLHPC (ECM-02).