Tensile Deformation of Ni/Ti Multilayers: Coupled Effects of Modulation Period and Strain Rate from Molecular Dynamics Simulations

Editorial Board PCSS Journal; Oleksandr Palchekovskyi; Andrii Orlov; Yurii Yavorskyi; Ivan Kruhlov

doi:10.15330/pcss.27.3.613-621

Authors

Oleksandr Palchekovskyi National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
Andrii Orlov National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
Yurii Yavorskyi National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
Ivan Kruhlov National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine

DOI:

https://doi.org/10.15330/pcss.27.3.613-621

Keywords:

Molecular Dynamics, Modulation Periods, Uniaxial Tension, Mechanical Properties, Ni/Ti Multilayers, Dislocation Density

Abstract

The mechanical response of Ni/Ti multilayers is governed by the interplay between interface-mediated deformation and structural transformations in the constituent layers. Here, molecular dynamics simulations are used to investigate the tensile deformation of planar Ni/Ti multilayers with modulation periods of 28.6 nm – 9.5 nm over strain rates of 10⁸ s^-1– 10¹⁰ s^-1. Decreasing the modulation period reduces the tensile strength by ~8% and substantially modifies the post-yield deformation, including the partitioning of dislocation activity between the Ni and Ti layers and the formation and persistence of deformation-induced BCC Ti. Increasing the strain rate has a comparatively weak effect on tensile strength but systematically delays the structural transformations. Pronounced stacking faults in Ni develop at ~8% strain at 10⁸ s^-1 but only at ~13% at 10¹⁰ s^-1. At the highest strain rate, the HCP-to-BCC transformation in Ti is also delayed and becomes more abrupt, producing finer and more dispersed BCC regions. Overall, the results show that the modulation period primarily determines the deformation pathway and distribution of plasticity between the constituent layers, whereas the strain rate primarily controls the onset and kinetics of the deformation processes.

References

Y. Fu et al., TiNi-based thin films in MEMS applications: a review, Sensors and Actuators A: Physical, 112, 395–408 (2004); https://doi.org/10.1016/j.sna.2004.02.019

T. Lehnert et al., A new fabrication process for Ni–Ti shape memory thin films, Materials Science and Engineering: A, 273, 713–716 (1999); https://doi.org/10.1016/S0921-5093(99)00402-5

H. Cho et al, Fabrication and characterization of Ti–Ni shape memory thin film using Ti/Ni multilayer technique, Science and Technology of Advanced Materials, 6(6), 678–683 (2005); https://doi.org/10.1016/j.stam.2005.05.006

I. Kruhlov et al., Structural phase transitions in Ni/Ag/Ti and Ni/Cu/Ti tri-layered thin films, Vacuum, 233, 11399 (2025); https://doi.org/10.1016/j.vacuum.2024.113999

M.A. Hollanders et al., Amorphization along interfaces and grain boundaries in polycrystalline multilayers: an X-ray-diffraction study of Ni/Ti multilayers, Physical Review B, 42(9), 5481 (1990); https://doi.org/10.1103/PhysRevB.42.5481

O. Palchekovskyi et al., The effect of Ni/Ti layered stack thickness on the interface amorphization behavior, Physica Scripta, 100, 075994 (2025); https://doi.org/10.1088/1402-4896/adeafb

A. Biswas et al., Early recrystallization of Ni/Ti multilayer due to disorder in the Ni layer, Journal of Applied Physics, 127, 165304 (2020); https://doi.org/10.1063/5.0008177

S. I. Konorev et al., Molecular Dynamics Study Of The Interface Amorphization In Ni/Ti Bi-Layered System, 2024 IEEE 42nd International Conference on Electronics and Nanotechnology (ELNANO) (2024); https://doi.org/10.1109/ELNANO63394.2024.10756916

L. Lu et al., Molecular dynamics simulation of effects of interface imperfections and modulation periods on Cu/Ta multilayers, Computational Materials Science, 143, 63–70 (2018); https://doi.org/10.1016/j.commatsci.2017.10.034

A.-S. Tran, Phase transformation and interface fracture of Cu/Ta multilayers: A molecular dynamics study, Engineering Fracture Mechanics, 239, 107292 (2020); https://doi.org/10.1016/j.engfracmech.2020.107292

T.-N. Vu et al., Interfacial strength and deformation mechanism of Ni/Co multilayers under uniaxial tension using molecular dynamics simulation, Materials Today Communications, 30, 103088 (2022); https://doi.org/10.1016/j.mtcomm.2021.103088

L. Wan et al., BCC stabilization and growth stress behavior in Ti/V multilayers, Thin Solid Films, 616, 555–561 (2016); https://doi.org/10.1016/j.tsf.2016.09.017

Z.Q. Hou et al., Phase transformation-induced strength softening in Ti/Ta nanostructured multilayers: Coherent interface vs phase boundary, Materials Science and Engineering: A, 684, 78–83 (2017); https://doi.org/10.1016/j.msea.2016.12.040

H. Zhang et al., Strain direction dependency of deformation mechanisms in an HCP-Ti crystalline by molecular dynamics simulations, Computational Materials Science, 172, 109328 (2020); https://doi.org/10.1016/j.commatsci.2019.109328

M.-J. Su et al., Molecular dynamics study of coupled layer thickness and strain rate effect on tensile behaviors of Ti/Ni multilayered nanowires, Chinese Physics B, 30, 096201 (2021); https://doi.org/10.1088/1674-1056/abf10a

P. Hirel, Atomsk: A tool for manipulating and converting atomic data files, Computer Physics Communications, 197, 212-219 (2015); https://doi.org/10.1016/j.cpc.2015.07.012

S. Plimpton, Fast parallel algorithms for short-range molecular dynamics, Journal of computational physics, 117(1), 1-19 (1995); https://doi.org/10.1006/jcph.1995.1039

Y.-K. Kim et al., Development and application of Ni-Ti and Ni-Al-Ti 2NN-MEAM interatomic potentials for Ni-base superalloys, Computational Materials Science, 139, 225-233 (2017); https://doi.org/10.1016/j.commatsci.2017.08.002

B. Liu et al., Molecular dynamics simulation of the porosity effect on transformation mechanism of nanocrystalline porous NiTi shape memory alloy, Materials Today Communications, 34, 105320 (2023); https://doi.org/10.1016/j.mtcomm.2023.105320

A. Stukowski, Visualization and analysis of atomistic simulation data with OVITO–the Open Visualization Tool, Modelling and simulation in materials science and engineering, 18(1), 015012 (2010); https://doi.org/10.1088/0965-0393/18/1/015012

Y. Zhang et al., Tensile and compressive behavior of TiN/Cu layered composites: A molecular dynamics study, Computational Materials Science, 271, 114817 (2026); https://doi.org/10.1016/j.commatsci.2026.114817