Sheared solid materials |
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Authors: | Akira Onuki Akira Furukawa Akihiko Minami |
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Institution: | (1) Department of Physics, Kyoto University, 606-8502 Kyoto, Japan |
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Abstract: | We present a time-dependent Ginzburg-Landau model of nonlinear elasticity in solid materials. We assume that the elastic energy
density is a periodic function of the shear and tetragonal strains owing to the underlying lattice structure. With this new
ingredient, solving the equations yields formation of dislocation dipoles or slips. In plastic flow high-density dislocations
emerge at large strains to accumulate and grow into shear bands where the strains are localized. In addition to the elastic
displacement, we also introduce the local free volumem. For very smallm the defect structures are metastable and long-lived where the dislocations are pinned by the Peierls potential barrier. However,
if the shear modulus decreases with increasingm, accumulation ofm around dislocation cores eventually breaks the Peierls potential leading to slow relaxations in the stress and the free energy
(aging). As another application of our scheme, we also study dislocation formation in two-phase alloys (coherency loss) under
shear strains, where dislocations glide preferentially in the softer regions and are trapped at the interfaces. |
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Keywords: | Plastic flow dislocations free volume aging two-phase alloys incoherency |
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