Formation of twins in sapphire under shock wave loading: Atomistic simulations

AY Kuksin and AV Yanilkin, JOURNAL OF APPLIED PHYSICS, 111, 033513 (2012).

DOI: 10.1063/1.36813211

This work is devoted to molecular dynamics (MD) simulation of shock-wave loading of sapphire (alpha-Al2O3). Defect free sapphire and sapphire with the microcrack are considered. Homogeneous nucleation and growth of rhombohedral twins are observed in single crystal alumina. A fast mechanism of plastic deformation is revealed under shock-wave loading of sapphire with microcrack. Rhombohedral twins nucleate and grow as a result of a two stage process. At the first stage the formation of a new type of linear defect takes place in the shock wave front, which is initiated at the surface of the microcrack. At the second stage the rhombohedral twins grow from the primary linear defects and combine with each other. The results are confirmed by first principles calculations. (C) 2012 American Institute of Physics. doi:10.1063/1.3681321

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