Molecular dynamics study of coupled layer thickness and strain rate effect on tensile behaviors of Ti/Ni multilayered nanowires*

Abstract

Novel properties and applications of multilayered nanowires (MNWs) urge researchers to understand their mechanical behaviors comprehensively. Using the molecular dynamic simulation, tensile behaviors of Ti/Ni MNWs are investigated under a series of layer thickness values (1.31, 2.34, and 7.17 nm) and strain rates ( 1.0 × 10 8 s − 1 ≤ ε . ≤ 5.0 × 10 10 s − 1 ). The results demonstrate that deformation mechanisms of isopachous Ti/Ni MNWs are determined by the layer thickness and strain rate. Four distinct strain rate regions in the tensile process can be discovered, which are small, intermediate, critical, and large strain rate regions. As the strain rate increases, the initial plastic behaviors transform from interface shear (the shortest sample) and grain reorientation (the longest sample) in small strain rate region to amorphization of crystalline structures (all samples) in large strain rate region. Microstructure evolutions reveal that the disparate tensile behaviors are ascribed to the atomic fractions of different structures in small strain rate region, and only related to collapse of crystalline atoms in high strain rate region. A layer thickness-strain rate-dependent mechanism diagram is given to illustrate the couple effect on the plastic deformation mechanisms of the isopachous nanowires. The results also indicate that the modulation ratio significantly affects the tensile properties of unequal Ti/Ni MNWs, but barely affect the plastic deformation mechanisms of the materials. The observations from this work will promote theoretical researches and practical applications of Ti/Ni MNWs.

Effect of void size and Mg contents on plastic deformation behaviors of Al–Mg alloy with pre-existing void: Molecular dynamics study

“…[26] Effect of layer thickness and strain rate on mechanical properties of Ti/Ni multilayered nanowires is reported. [27] Bahramyan et al simulated the interaction between edge dislocation and void in pure Al and Al-Mg alloys. [28] Moreover, void growth in high entropy alloys has also been studied.…”

Strengthening and softening in gradient nanotwinned FCC metallic multilayers

“…Periodic boundary conditions are maintained in x and y directions. [22][23][24] The substrates include the boundary, thermostat, and Newtonian layers (Fig. 1).…”

Layer thickness dependent plastic deformation mechanism in Ti/TiCu dual-phase nano-laminates

“…Molecular dynamics (MD) simulation provides an alternative method to experiments, which plays an important role in understanding the deformation mechanism in metallic materials. [35][36][37][38] Actually, the mechanical properties of the crystalline/amorphous nanolaminates have been investigated in the past few years using MD simulation. [39][40][41][42] Tran and Fang [39] reported that the plastic deformation zones increase as the thickness of each layer decreases in crystalline/amorphous Cu/CuTa nanolaminates.…”