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The mechanical behavior of nanoporous monocrystal aluminum subjected to uniaxial compressive loading at a rate of 2109 s- 1 along [110] crystallographic orientation is studied using molecular dynamics simulations. Subjected to such a loading, nanovoids act as the effective sources of dislocation nucleation and emission, four of the twelve {111}110 slip systems may be activated. With the same strain of 3.8%, dislocation nucleation will occur in both the sample of multiple voids and that with a single void. The configuration of multiple voids decreases the required stress for the onset of dislocation nucleation and emission in comparison with the sample with an isolated void of the same size. Because of the emission of trial partials, the accumulation of dislocation density can be changed into a piecewise linear process by the dislocation density propagation rate dd/d: in the initial stage of plastic deformation we obtain dd/d1.071018 m-2, but this changes to dd/d5.361018 m-2 at higher deformation. The velocity of dislocation is calculated to be subsonic and is a variable value during the plastic deformation. Dislocation loop pairs emit from the same void, glide and approach to each other, leading to the reduction of dislocation velocity. Then one loop of each pair continues to glide to intersect mutually and finally interact with the loops emitted from other voids, causing a strain hardening to reach the peak flow stress of 4.3 GPa. There is a post-yield softening corresponding to the onset of rapid dislocation density proliferation at higher dislocation densities. With the temperature evolution of the sample with multiple voids during plastic deformation, the density of mobile dislocations is calculated to be one magnitude lower than the total dislocation density. There is a decrease of mobile dislocation densities at large strains, showing that the mobile dislocation are diminished by the formation of dislocation forest and junctions. At the onset of their nucleation, the dislocations are all Shockley partials, however, when dislocation intersection happens, the majority are still Shockley partials, while the rest consists of Frank partials, perfect fcc dislocations and other dislocation ingredients. Voids collapse at the strain of 11.8%. No twins are found in the present simulation due to the high stacking-fault energy of aluminum. Prismatic dislocation loop emission is observed in this simulation.
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Keywords:
- molecular dynamics /
- nanovoid /
- nanoporous /
- dislocation
[1] Lubarda V, Schneider M, Kalantar D, Remington B, Meyers M 2004 Acta Mater. 52 1397
[2] Shikama T, Pells G 1983 Philos. Mag. A 47 369
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[6] Deng X L, Zhu W J, He H L, Wu D X, Jing F Q 2006 Acta Phys. Sin. 55 4767 (in Chinese) [邓小良, 祝文军, 贺红亮, 伍登学, 经福谦 2006 55 4767]
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[8] Tang Y, Bringa E M, Remington B A, Meyers M A 2011 Acta Mater. 59 1354
[9] Bhatia M, Solanki K, Moitra A, Tschopp M 2013 Metall. Mater. Trans. A 44 617
[10] Seppälä E, Belak J, Rudd R 2004 Phys. Rev. Lett. 93 245503
[11] Deng X L, Zhu W J, Song Z F, He H L, Jing F Q 2009 Acta Phys. Sin. 58 4772 (in Chinese) [邓小良, 祝文军, 宋振飞, 贺红亮, 经福谦 2009 58 4772]
[12] Sun X Y, Xu G K, Li X, Feng X Q, Gao H 2013 J. Appl. Phys. 113 023505
[13] Erhart P, Bringa E M, Kumar M, Albe K 2005 Phys. Rev. B 72 052104
[14] Ruestes C, Bringa E, Stukowski A, Rodríguez Nieva J, Tang Y, Meyers M 2014 Comp. Mater. Sci. 88 92
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[16] Rodriguez-Nieva J, Ruestes C, Tang Y, Bringa E 2014 Acta Mater. 80 67
[17] Bringa E M, Traiviratana S, Meyers M A 2010 Acta Mater. 58 4458
[18] Zhu W, Song Z, Deng X, He H, Cheng X 2007 Phys. Rev. B 75 024104
[19] Plimpton S 1995 J. Comput. Phys. 117 1
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[22] Stukowski A, Albe K 2010 Modell. Simul. Mater. Sci. Eng. 18 085001
[23] Wu L, Markenscoff X 1996 J Elast. 44 131
[24] Yamakov V, Wolf D, Phillpot S R, Mukherjee A K, Gleiter H 2002 Nature Mater. 1 45
[25] Liao X, Zhou F, Lavernia E, He D, Zhu Y 2003 Appl. Phys. Lett. 83 5062
[26] Yuan L, Jing P, Liu Y H, Xu Z H, Shan D B, Guo B 2014 Acta Phys. Sin. 63 016201 (in Chinese) [袁林, 敬鹏, 刘艳华, 徐振海, 单德彬, 郭斌 2014 63 016201]
[27] Higginbotham A, Bringa E M, Marian J, Park N, Suggit M, Wark J S 2011 J. Appl. Phys. 109 063530
[28] Hodowany J, Ravichandran G, Rosakis A, Rosakis P 2000 Exp. Mech. 40 113
[29] Ferguson W, Kumar A, Dorn J 1967 J Appl Phys 38 1863
[30] Gorman J, Wood D, Vreeland Jr T 1969 J Appl Phys 40 833
[31] Simar A, Bréchet Y, De Meester B, Denquin A, Pardoen T 2007 Acta Mater. 55 6133
[32] Hordon M, Averbach B 1961 Acta Metall. 9 237
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[1] Lubarda V, Schneider M, Kalantar D, Remington B, Meyers M 2004 Acta Mater. 52 1397
[2] Shikama T, Pells G 1983 Philos. Mag. A 47 369
[3] Russell K 1978 Acta Metall. 26 1615
[4] Yang J H, Zhang T H 2005 Chin. Phys. 14 556
[5] Marian J, Knap J, Ortiz M 2004 Phys. Rev. Lett. 93 165503
[6] Deng X L, Zhu W J, He H L, Wu D X, Jing F Q 2006 Acta Phys. Sin. 55 4767 (in Chinese) [邓小良, 祝文军, 贺红亮, 伍登学, 经福谦 2006 55 4767]
[7] Rudd R E 2009 Philos. Mag. 89 3133
[8] Tang Y, Bringa E M, Remington B A, Meyers M A 2011 Acta Mater. 59 1354
[9] Bhatia M, Solanki K, Moitra A, Tschopp M 2013 Metall. Mater. Trans. A 44 617
[10] Seppälä E, Belak J, Rudd R 2004 Phys. Rev. Lett. 93 245503
[11] Deng X L, Zhu W J, Song Z F, He H L, Jing F Q 2009 Acta Phys. Sin. 58 4772 (in Chinese) [邓小良, 祝文军, 宋振飞, 贺红亮, 经福谦 2009 58 4772]
[12] Sun X Y, Xu G K, Li X, Feng X Q, Gao H 2013 J. Appl. Phys. 113 023505
[13] Erhart P, Bringa E M, Kumar M, Albe K 2005 Phys. Rev. B 72 052104
[14] Ruestes C, Bringa E, Stukowski A, Rodríguez Nieva J, Tang Y, Meyers M 2014 Comp. Mater. Sci. 88 92
[15] Ruestes C, Bringa E, Stukowski A, Rodríguez Nieva J, Bertolino G, Tang Y, Meyers M 2013 Scripta Mater. 68 817
[16] Rodriguez-Nieva J, Ruestes C, Tang Y, Bringa E 2014 Acta Mater. 80 67
[17] Bringa E M, Traiviratana S, Meyers M A 2010 Acta Mater. 58 4458
[18] Zhu W, Song Z, Deng X, He H, Cheng X 2007 Phys. Rev. B 75 024104
[19] Plimpton S 1995 J. Comput. Phys. 117 1
[20] Mishin Y, Farkas D, Mehl M, Papaconstantopoulos D 1999 Phys. Rev. B 59 3393
[21] Li J 2003 Modell. Simul. Mater. Sci. Eng. 11 173
[22] Stukowski A, Albe K 2010 Modell. Simul. Mater. Sci. Eng. 18 085001
[23] Wu L, Markenscoff X 1996 J Elast. 44 131
[24] Yamakov V, Wolf D, Phillpot S R, Mukherjee A K, Gleiter H 2002 Nature Mater. 1 45
[25] Liao X, Zhou F, Lavernia E, He D, Zhu Y 2003 Appl. Phys. Lett. 83 5062
[26] Yuan L, Jing P, Liu Y H, Xu Z H, Shan D B, Guo B 2014 Acta Phys. Sin. 63 016201 (in Chinese) [袁林, 敬鹏, 刘艳华, 徐振海, 单德彬, 郭斌 2014 63 016201]
[27] Higginbotham A, Bringa E M, Marian J, Park N, Suggit M, Wark J S 2011 J. Appl. Phys. 109 063530
[28] Hodowany J, Ravichandran G, Rosakis A, Rosakis P 2000 Exp. Mech. 40 113
[29] Ferguson W, Kumar A, Dorn J 1967 J Appl Phys 38 1863
[30] Gorman J, Wood D, Vreeland Jr T 1969 J Appl Phys 40 833
[31] Simar A, Bréchet Y, De Meester B, Denquin A, Pardoen T 2007 Acta Mater. 55 6133
[32] Hordon M, Averbach B 1961 Acta Metall. 9 237
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