Tensile mechanical performance of Ni–Co alloy nanowires by molecular dynamics simulation

Lu, Xuefeng; Pei, Yang; Luo, Jianhua; Ren, Junqiang; Han, Xue; Ding, Yutian

doi:10.1039/c9ra04294f

Cited by 23 publications

(8 citation statements)

References 37 publications

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“…At the same time, it also leads to an increase in the GB atomic fraction and a corresponding decrease in the GI atomic fraction, which is similar to Figure 11 and the existing research results. [29] Figure 13 shows the atomic structure changes in shearing process at 100 and 900 K. In Figure 13a1-f1, the strain near GB is more obvious than that at GI. When the strain value is 0.125, although stacking faults appear in two cases in Figure 13b,e, unlike conventional stacking faults at low temperatures (yellow arrows), irregular stacking faults will appear at high temperatures (purple arrows).…”

Section: Temperature Effect On Mechanical Behaviormentioning

confidence: 99%

Effect of Co Content and Temperature on Shear Mechanical Properties of Nano‐Polycrystalline Ni–Co Alloy

Chen

Ren

et al. 2022

Physica Status Solidi (b)

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Herein, the effects of different Co content and temperature factors on the shear mechanical properties of nano‐polycrystalline nickel–cobalt alloy are analyzed by molecular dynamics (MD) simulations. It is found in the work that the highest shear modulus of 63.03 GPa is obtained when the Co content is 10%, attributed to the lattice distortion caused by the difference in the lattice parameters between two elements. During the shearing process, the multilevel twins are present with intensification of the deformation process, resulting in excellent dynamic shear performance. Shockley dislocations will drive the stacking faults and other partial dislocations to constitute a tetrahedral edge, and finally forms a tetrahedral structure. In addition, as the temperature of the shear environment increases, the highest strain and stress decrease. The grain boundary atoms increase significantly, and the atoms inside the grains decrease accordingly. As the degree of atomic disorder increases, the grain boundaries will melt gradually. The decrease of partial dislocation density can weaken the entanglement effect caused by dislocations. The previous conclusions promote the product development and application of nano‐polycrystalline alloys in the future, and provide important guidance significant for the engineering application of nickel–cobalt alloys.

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Section: Temperature Effect On Mechanical Behaviormentioning

confidence: 99%

Effect of Co Content and Temperature on Shear Mechanical Properties of Nano‐Polycrystalline Ni–Co Alloy

Chen

Ren

et al. 2022

Physica Status Solidi (b)

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“…The yield stress of well-annealed wires of 1 mm in diameter increases from 47.7 MPa in pure Ni to 68.3 MPa in the Ni-0.3Co weight fraction alloy, with the flow stress increasing from 176 to 262 MPa 20 . MD simulations predict that the Ni-Co nanowires’ strength increases to about 10 GPa upon the addition of 0.05 to 0.10 mole fractions of Co 21 . Contrary to this expectation, we find here that the strength of defect-free Ni-Co nanoparticles actually decreases with the addition of Co, resulting in the counter-intuitive solute-softening effect.…”

Section: Introductionmentioning

confidence: 99%

The impact of alloying on defect-free nanoparticles exhibiting softer but tougher behavior

Bisht

Koju

et al. 2021

Nat Commun

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The classic paradigm of physical metallurgy is that the addition of alloying elements to metals increases their strength. It is less known if the solution-hardening can occur in nano-scale objects, and it is totally unknown how alloying can impact the strength of defect-free faceted nanoparticles. Purely metallic defect-free nanoparticles exhibit an ultra-high strength approaching the theoretical limit. Tested in compression, they deform elastically until the nucleation of the first dislocation, after which they collapse into a pancake shape. Here, we show by experiments and atomistic simulations that the alloying of Ni nanoparticles with Co reduces their ultimate strength. This counter-intuitive solution-softening effect is explained by solute-induced local spatial variations of the resolved shear stress, causing premature dislocation nucleation. The subsequent particle deformation requires more work, making it tougher. The emerging compromise between strength and toughness makes alloy nanoparticles promising candidates for applications.

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“…The modeling method of Al-Mg and Al-Cu alloys for MD study has been adopted from numerous previous works. 4,5,38,39 The effects of these parameters on the dislocation nucleation, propagation mechanism and material properties such as hardness and reduced modulus have been discussed (section 3.1). Then, tensile test simulations have been performed to obtain the mechanical properties such as elastic modulus, yield strength and Poisson's ratio of the alloy material (section 3.2).…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of mechanical properties of aluminum-copper alloys at nanoscale

et al. 2021

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Nanoindentation is a powerful tool capable of providing fundamental insights of material elastic and plastic response at the nanoscale. Alloys at nanoscale are particularly interesting as the local heterogeneity and deformation mechanism revealed by atomistic study offers a better way to understand hardening mechanism to build a stronger material. In this work, nanoindentation in Al-Mg alloys are studied using atomistic simulations to investigate the effects of loading direction, alloying percentages of Mg via dislocation-driven mechanisms. Also, finite element (FE) nanoindentation simulations are performed using MD tensile test results as input parameters for the FE simulations. Material properties, such as hardness and reduced modulus, are computed from both the FE and MD simulations and then compared. Considering the fundamental difference between these two numerical approaches, the FE results obtained from the present study conform fairly with those from MD simulations. This paves a way into finding material properties of alloys with reduced simulation time and cost by using FE instead of MD. The results have been presented as load-displacement analysis, dislocation density, dislocation loops nucleation and propagation, von-Mises stress distribution and surface imprints. The techniques adopted in this paper to incorporate atomistic data into FE simulations can be further extended for finding other mechanical and fracture properties for complex alloy materials.

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Tensile mechanical performance of Ni–Co alloy nanowires by molecular dynamics simulation

Abstract: The addition of a little Co can promote the formation of Frank and other fixed dislocations, making the alloy system have high yield strength. The defects in nanowires accelerated the occurrence of yield behavior.

Cited by 23 publications

References 37 publications

Effect of Co Content and Temperature on Shear Mechanical Properties of Nano‐Polycrystalline Ni–Co Alloy

Effect of Co Content and Temperature on Shear Mechanical Properties of Nano‐Polycrystalline Ni–Co Alloy

The impact of alloying on defect-free nanoparticles exhibiting softer but tougher behavior

Numerical investigation of mechanical properties of aluminum-copper alloys at nanoscale

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