MSA  Vol.8 No.12 , November 2017
Molecular Dynamics Simulation of Grain Refinement in a Polycrystalline Material under Severe Compressive Deformation
Abstract: Grain refinement in a polycrystalline material resulting from severe compressive deformation was simulated using molecular dynamics. A simplified model with four square grains surrounded by periodic boundaries was prepared, and compressive deformation was imposed by shortening the length in the y direction. The model first deformed elastically, and the compressive stress increased monotonically. Inelastic deformation was then initiated, and the stress decreased drastically. At that moment, dislocation or slip was initiated at the grain boundaries or triple junction and then spread within the grains. New grain boundaries were then generated in some of the grains, and sub-grains appeared. Finally, a microstructure with refined grains was obtained. This process was simulated using two types of grain arrangements and three different combinations of crystal orientations. Grain refinement generally proceeded in a similar fashion in each scenario, whereas the detailed inelastic deformation and grain refinement behavior depended on the initial microstructure.
Cite this paper: Uehara, T. (2017) Molecular Dynamics Simulation of Grain Refinement in a Polycrystalline Material under Severe Compressive Deformation. Materials Sciences and Applications, 8, 918-932. doi: 10.4236/msa.2017.812067.

[1]   Sabirov, I., Murashkin, M.Y. and Valiev, R.Z. (2013) Nanostructured Aluminum Alloys Produced by Severe Plastic Deformation: New Horizons in Development. Materials Science and Engineering A, 560, 1-24.

[2]   Huang, Y. and Langdon, T.G. (2014) Advances in Ultrafine-Grained Materials. Materials Today, 16, 85-93.

[3]   Segal, V.M. (1999) Equal Channel Angular Extrusion: From Macromechanics to Structure Formation. Materials Science and Engineering A, 271, 322-333.

[4]   Beyerlein, I.J. and Toth, L.S. (2009) Texture Evolution in Equal-Channel Angular Extrusion. Progress in Materials Science, 54, 427-510.

[5]   Saito, Y., Utsunomiya, H., Tsuji, N. and Sakai, T. (1999) Novel Ultra-High Straining Process for Bulk Materials—Development of the Accumulative Roll-bonding (ARB) Process. Acta Materialia, 47, 579-583.

[6]   Kamikawa, N. and Furuhara, T. (2013) Accumulative Channel-Die Bonding (ACCB): A New Severe Plastic Deformation Process to Produce Bulk Nanostructured Metals. Journal of Materials Processing Technology, 213, 1412-1418.

[7]   Sidor, J., Miroux, A., Petrov, R. and Kestens, L. (2008) Microstructural and CrystalloGraphic Aspects of Conventional and Asymmetric Rolling Processes. Acta Materialia, 56, 2495-2507.

[8]   Rehrl, C., Kleber, S., Renk, O., and Pippan, R. (2012) Effect of Grain Size in Compression Deformation on the Microstructural Evolution of an Austenitic Stainless Steel. Materials Science and Engineering A, 540, 55-62.

[9]   Ghosh, P. Renk, O. and Pippan, R.R. (2017) Microtexture Analysis of Restoration Mechanisms during High Pressure Torsion of Pure Nickel. Materials Science and Engineering A, 684, 101-109.

[10]   Van Swygenhoven, H., Caro, A. and Farkas, D. (2001) A Molecular Dynamics Study of Polycrystalline Fcc Metals at the Nanoscale: Grain Boundary Structure and Its Influence on Plastic Deformation. Materials Science and Engineering A, 309-310, 440-444.

[11]   Wolf, D., Yamakov, V., Phillpot, S.R., Mukherjee, A. and Gleiter, H. (2005) Deformation of Nanocrystalline Materials by Molecular-Dynamics Simulation: Relationship to Experiments? Acta Materialia, 53, 1-40.

[12]   Trautt, Z.T. and Mishin, Y. (2012) Grain Boundary Migration and Grain Rotation Studied by Molecular Dynamics. Acta Materialia, 60, 2407-2424.

[13]   Farkas, D. (2013) Atomistic Simulations of Metallic Microstructures. Current Opinion in Solid State and Materials Science, 17, 284-297.

[14]   Spearot, D.E. and Sangid, M.D. (2014) Insights on Slip Transmission at Grain Boundaries from Atomistic Simulations. Current Opinion in Solid State and Materials Science, 18, 188-195.

[15]   Hahn, E.N. and Meyers, M.A. (2015) Grain-size Dependent Mechanical Behavior of Nanocrystalline Metals. Materials Science and Engineering A, 646, 101-134.

[16]   Uehara, T., Wakabayashi, N., Hirabayashi, Y. and Ohno, N. (2008) An Atomistic Study of Grain Boundary Stability and Crystal Rearrangement Using Molecular Dynamics Techniques. International Journal of Mechanical Sciences, 50, 956-965.

[17]   Uehara, T., Asai, C. and Ohno, N. (2009) Molecular Dynamics Simulation of Shape-Memory Behaviour Using a Multi-Grain Model. Modelling and Simulation in Materials Science and Engineering, 17, Article ID: 035011.

[18]   Uehara, T. (2015) Molecular Dynamics Simulation on Transformation-Induced Plastic Deformation Using a Lennard-Jones Model. Key Engineering Materials, 626, 414-419.

[19]   Uehara, T. (2017) Molecular Dynamics Simulation of the Variation in the Microstructure of a Polycrystalline Material under Tensile Load. Key Engineering Materials, 748, 375-380.

[20]   Uehara, T. (2017) Molecular Dynamics Simulation of Microstructural Change in a Polycrystalline FCC Metal under Compression. Proceedings of XIV International Conference on Computational Plasticity, Barcelona, 5-7 September 2017, 106-113.