Shock responses of nanoporous aluminum by molecular dynamics simulations

Xiang, Meizhen; Cui, Junzhi; Yang, Yantao; Liao, Yi; Wang, Kun; Chen, Yun; Chen, Jun

doi:10.1016/j.ijplas.2017.05.008

Cited by 92 publications

(13 citation statements)

References 53 publications

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“…As the shear loops expand further, the leading Shockley partial dislocations on two different {111} slip planes meet and interact, forming the dislocation and stacking fault structure with four-fold symmetry with respect to the loading direction, as illustrated in Figure 5. Almost identical stacking fault structures were also observed in the shock responses of single crystal Al with nanoporous [58]. This means that the key to the creation of this stacking fault structure is not the type of initial defect, but the initial defect provides the dislocation nucleation site.…”

Section: Shock Compression Process At Low Piston Velocitiesmentioning

confidence: 65%

Spallation Characteristics of Single Crystal Aluminum with Copper Nanoparticles Based on Atomistic Simulations

et al. 2021

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In this study, the effects of Cu nanoparticle inclusion on the dynamic responses of single crystal Al during shockwave loading and subsequent spallation processes have been explored by molecular dynamics simulations. At specific impact velocities, the ideal single crystal Al will not produce dislocation and stacking fault structure during shock compression, while Cu inclusion in an Al–Cu nanocomposite will lead to the formation of a regular stacking fault structure. The significant difference of a shock-induced microstructure makes the spall strength of the Al–Cu nanocomposite lower than that of ideal single crystal Al at these specific impact velocities. The analysis of the damage evolution process shows that when piston velocity up ≤ 2.0 km/s, due to the dense defects and high potential energy at the interface between inclusions and matrix, voids will nucleate preferentially at the inclusion interface, and then grow along the interface at a rate of five times faster than other voids in the Al matrix. When up ≥ 2.5 km/s, the Al matrix will shock melt or unloading melt, and micro-spallation occurs; Cu inclusions have no effect on spallation strength, but when Cu inclusions and the Al matrix are not fully diffused, the voids tend to grow and coalescence along the inclusion interface to form a large void.

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Section: Shock Compression Process At Low Piston Velocitiesmentioning

confidence: 65%

Spallation Characteristics of Single Crystal Aluminum with Copper Nanoparticles Based on Atomistic Simulations

et al. 2021

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“…With further deformation, the high shear strain area extends to the front surface of the void, resulting in a conical void, as shown in Fig 6(b)–6(d) . Unlike the plastic mechanism under v = 0.5 km/s, the void collapse in this case is dominated by the internal jetting mechanism [ 12 ], which leads to filling of the void vacuum in the longitudinal direction.…”

Section: Resultsmentioning

confidence: 99%

“…Nanoporous metals play an important role in the fields of military, aeronautical engineering, energy, catalysis, environmental protection and biomedicine [1]. Many researchers have investigated the dynamics response of porous materials by experiments [2][3][4][5][6][7], theoretical methods [8,9,11] and numerical simulations [12][13][14][15]. For example, Levy [2] investigated the collision of a planar shock wave with a rigid porous material in a 75 mm × 75 mm shock tube.…”

Section: Introductionmentioning

confidence: 99%

“…The proposed approach is demonstrated by comparison with experimental data; Following the constitutive framework developed by Molinari and Ravichandran [ 10 ] for the analysis of steady shock waves in dense metals, Czarnota et al [ 11 ] proposed an analytical approach of steady state propagation of plastic shocks in porous metals. The results obtained in their work provided a new insight in the fundamental understanding of shock waves in porous media; Xiang et al [ 12 ] presented systematic investigations examining the shock responses of nanoporous aluminum by nonequilibrium molecular dynamics simulations, they proposed a continuum wave reflection theory and a resolved shear stress model to explain the distribution of dislocation nucleation sites; Liao et al [ 13 ] presented systematic investigations on energy dissipation and void collapse in graded nanoporous nickel by non-equilibrium molecular dynamics simulations. It is found that void size gradient influences the time history path of the energy dissipation; Li et al [ 14 ] investigated shock response of nanoporous Mg by nonequilibrium MD simulations.…”

Section: Introductionmentioning

confidence: 99%

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Anisotropic shock responses of nanoporous Al by molecular dynamics simulations

Xia

et al. 2021

PLoS ONE

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Mechanical responses of nanoporous aluminum samples under shock in different crystallographic orientations (<100>, <111>, <110>, <112> and <130>) are investigated by molecular dynamics simulations. The shape evolution of void during collapse is found to have no relationship with the shock orientation. Void collapse rate and dislocation activities at the void surface are found to strongly dependent on the shock orientation. For a relatively weaker shock, void collapses fastest when shocked along the <100> orientation; while for a relatively stronger shock, void collapses fastest in the <110> orientation. The dislocation nucleation position is strongly depended on the impacting crystallographic orientation. A theory based on resolved shear stress is used to explain which slip planes the earliest-appearing dislocations prefer to nucleate on under different shock orientations.

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“…At present, MD simulation has become a resourceful tool in studying various deformation mechanisms in materials at atomistic level. Recent MD researches [15][16][17][18][19][20][21][22] have shown many microstructure effects related to spallation, such as the grain size, anisotropy and intrinsic defects. For exam-ple, it is found that when grain size decreases continuously to lower than nm, the yield strength of materials will change from an increasing trend to a decreasing trend, triggering the so-called inverse Hall-Petch effect [7,[23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Damage characteristic of aluminum nanorod under hypervelocity impact

Wu¹,

Shao²,

Zhan³

2019

Preprint

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Understanding the dynamic behavior of materials under hypervelocity impact is of great importance to develop new materials or structures for protective applications. The present work gives insight into the damage characteristic of aluminum nanorod under hypervelocity impact based on atomistic simulations. First of all, the propagation of impact wave is found to experience a rapid decaying because of its release from the side surface, which leads to a complex three-dimensional stress wave and two tension regions inside the nanorod. The damage mode under this tension state is found to be very different from the classical spallation. Due to the interaction of two release waves from the side and end surfaces, a temporary spall damage is observed and its initial tensile strength is close to that of bulk material. However, that early spall damage does not develop into a complete spall fracture. More importantly, all generated voids are found to be closed eventually after their coalescence. Furthermore, the mass continues expanding outward from the impact plane and finally causes a radial annular fragmentation. The annular fragmentation shows a clear crystalline direction dependence for low impact velocities. The number and the size of final fragments are found to follow a power law relationship for all impact velocities.

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Shock responses of nanoporous aluminum by molecular dynamics simulations

Cited by 92 publications

References 53 publications

Spallation Characteristics of Single Crystal Aluminum with Copper Nanoparticles Based on Atomistic Simulations

Spallation Characteristics of Single Crystal Aluminum with Copper Nanoparticles Based on Atomistic Simulations

Anisotropic shock responses of nanoporous Al by molecular dynamics simulations

Damage characteristic of aluminum nanorod under hypervelocity impact

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