Molecular dynamics simulations of the mechanical behavior of alumina coated aluminum nanowires under tension and compression

Rosandi, Yudi; Luu, Hoang-Thien; Urbassek, Herbert M.; Gunkelmann, Nina

doi:10.1039/d0ra01206h

Cited by 15 publications

(8 citation statements)

References 23 publications

(30 reference statements)

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“…By comparing the maximum stress value of the stress-strain curve, it can be seen that the crystals' tensile strength decreases with increasing ductility, with Ni having the highest yield stress, followed by Cu and Al, as expected given their ductility. In contrast to conventional tensile testing, where the stress-strain diagram is essentially smooth with a linear slope in the elastic region, after entering the plastic region, the tail of this stress-strain curve is characterized by a series of steps of rise and fall in the values, suggesting irreversibility of the process, which is in good agreement with the theory [21,33]. The phenomenon can be explained by the initial transition from elastic to plastic deformation.…”

Section: Microstructure Evolution Of Tensile Deformationsupporting

confidence: 80%

“…More specifically, MD simulation was used at the nanoscale level to simulate the elasto-plastic behavior of monocrystals in various orientations. Rosandi et al [21], investigated the mechanical properties of Al nanowires and alumina coated Al under tension and compression at various strain rates. Liang & Upmanyu [22], studied the size dependent elasticity of copper nanowires using a molecular statics methodology based on the embedded atom method (EAM) potential.…”

Section: Introductionmentioning

confidence: 99%

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Atomistic Simulation of the Effect of Temperature on Mechanical Properties of some Nano-Crystalline Metals

Igwe

Batsari

2022

Afr. Sci. Rep.

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For materials with high ductility, malleability and conductivity, temperature will have significant impact on the material properties. This is especially true for pure elemental metals which have a wide range of applications due to their ultrahigh strengths. Recently, the study of damage mechanism at the nano- and micro level has attracted a significant interest and research. However, the current understanding of deformation mechanisms in nanocrystalline metals in relation to atomic structure and behavior is insufficient. In this study, atomistic simulation of uniaxial tension at nano-scale was performed at a fixed rate of loading (500 ms^-1) on some nano-crystalline face centered cubic metals (Al, Cu, and Ni), to study the nature of tensile deformation at different temperatures using the embedded-atomic method (EAM) potential function. The simulation results show a rapid increase in the stress up to a maximum value followed by a sharp drop when the nanocrystal fails by ductile dislocation. The drop in the stress-strain curves can be attributed to the rearrangement of atoms to a new or modified crystalline structure. Additional simulations were run to study the effects of temperature on the stress-strain curve of nano-crystals. The result shows that increasing temperature weakens the ductility of these nanomaterials. In this investigation, the strain corresponding to yielding stress is observed to be lower with increasing temperature. Finally, the evolution of crystalline microstructure during the entire tensile process was investigated. The atomistic simulation result of tensile deformation at nanoscale obtained in this study agree with plasticity phenomenon observed in macroscale.

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Section: Microstructure Evolution Of Tensile Deformationsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Atomistic Simulation of the Effect of Temperature on Mechanical Properties of some Nano-Crystalline Metals

Igwe

Batsari

2022

Afr. Sci. Rep.

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“…30 Previous MD simulations of 4−7 nm Al nanowires with Al 2 O 3 coating show slight hardening only in compression due to increase in Al−O bonds. 31,32 These MD simulations had an oxide volume fraction of ∼50%, which is significantly different from the oxide volume fraction of ∼8% in the current study. MD simulations of 40 nm Al nanocubes were performed to understand the role of surface roughness and the oxide layer on dislocation loop formation and strain hardening.…”

contrasting

confidence: 80%

“…Compression of FIB-milled pillars with sputtered or atomic layer deposited metal or oxide coatings showed strain hardening with final dislocation densities comparable to the Al nanocubes due to the inability of dislocations to annihilate at free surfaces. , In contrast, Au nanowires coated with alumina had no change in plastic behavior . Previous MD simulations of 4–7 nm Al nanowires with Al 2 O 3 coating show slight hardening only in compression due to increase in Al–O bonds. , These MD simulations had an oxide volume fraction of ∼50%, which is significantly different from the oxide volume fraction of ∼8% in the current study.…”

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confidence: 80%

Extraordinary Strain Hardening from Dislocation Loops in Defect-Free Al Nanocubes

et al. 2022

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The complex interaction of crystalline defects leads to strain hardening in bulk metals. Metals with high stacking fault energy (SFE), such as aluminum, tend to have low strain hardening rates due to an inability to form stacking faults and deformation twins. Here, we use in situ scanning electron microscopy (SEM) mechanical compressions to find that colloidally synthesized defect-free 114 nm Al nanocubes combine a high linear strain hardening rate of 4.1 GPa with a high strength of 1.1 GPa. These nanocubes have a 3 nm selfpassivating oxide layer that has a large influence on mechanical behavior and the accumulation of dislocation structures. Postcompression transmission electron microcopy (TEM) imaging reveals stable prismatic dislocation loops and the absence of stacking faults. MD simulations relate the formation of dislocation loops and strain hardening to the surface oxide. These results indicate that slight modifications to surface and interfacial properties can induce enormous changes to mechanical properties in high SFE metals.

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“…´/ This strain rate is widely used in MD simulations of various metal and alloy materials [50][51][52]. The open-source tool (OVITO) [53] is used to visualize the atomic-level deformation process, and the common neighbor analysis (CNA) method [54] is utilized to analyze structure evolution.…”

mentioning

confidence: 99%

Atomistic simulations of mechanical characteristics dependency on relative density, grain size, and temperature of nanoporous tungsten

Hu¹,

Xu²,

Su³

et al. 2022

Phys. Scr.

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A series of atomistic simulations are adopted to explore the influences of relative density, grain size, and temperature on the tensile characteristics of nanoporous tungsten (NPW). Results illustrate that the dominant mechanism of deformation for monocrystalline NPW is the combination of twin boundaries (TBs) migration and 1/2<111> dislocation movement. The relative density, which has a positive relationship with stiffness and strength, significantly affects the mechanical properties of NPW. With relative density growing from 0.30 to 0.60, Young's modulus, UTS, and yield strength of monocrystalline NPW increase from 18.55, 0.65, and 0.45 GPa to 93.78, 2.93, and 2.59 GPa, respectively. Young's modulus and relative density have a quadratic relationship, meaning that the dominant deformation is the bending deformation of ligaments during the elastic stage. The scaling law for yield strength reveals that the axial yielding of ligaments dominates the yielding behavior of NPW. The relationship between mean grain size (5.00 ~ 17.07 nm) and strength follows the reverse Hall-Petch relation. Besides, the effect of temperature on mechanical characteristics is discussed. With the increase of temperature from 10 K to 1500 K, Young's modulus of monocrystalline NPW and nanocrystalline NPW (d = 5.00, 10.99, and 17.07 nm) decrease from 69.24, 51.73, 61.08, and 63.75 GPa to 48.98, 34.77, 44.65, and 49.05 GPa. The findings systematically reveal the mechanical properties of NPW under tension and provide guidance for its application.

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Molecular dynamics simulations of the mechanical behavior of alumina coated aluminum nanowires under tension and compression

Abstract: Alumina coatings increase the ductility of aluminum nanowires by reorganization of the Al–O layer and stabilization of bonds.

Cited by 15 publications

References 23 publications

Atomistic Simulation of the Effect of Temperature on Mechanical Properties of some Nano-Crystalline Metals

Atomistic Simulation of the Effect of Temperature on Mechanical Properties of some Nano-Crystalline Metals

Extraordinary Strain Hardening from Dislocation Loops in Defect-Free Al Nanocubes

Atomistic simulations of mechanical characteristics dependency on relative density, grain size, and temperature of nanoporous tungsten

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