WSEAS Transactions on Applied and Theoretical Mechanics
Print ISSN: 1991-8747, E-ISSN: 2224-3429
Volume 10, 2015
Twin Boundary Migration and Nanocrack Generation in Ultrafine-Grained Materials with Nanotwinned Structure
Authors: , , , ,
Abstract: A theoretical model is suggested which describes plastic flow and crack generation through twin boundary migration in nanotwinned metals (ultrafine-grained metallic materials containing high-density ensembles of nanoscale twins within grains). Within the suggested model, migration of twin boundaries under a mechanical load carries plastic deformation and leads to formation of wedge disclinations at the junctions of twin and grain boundaries. These disclinations create high local stresses that produce strengthening of nanotwinned metals and can induce nanocrack generation. Within the model, we calculate the flow stress as a function of twin thickness in nanotwinned metals in the situation where twin boundary migration significantly contributes to plastic flow. We also consider generation of nanocracks in nanotwinned metals during migration of twin boundaries and calculate the conditions for crack formation. Besides, our theoretical results and their comparison with corresponding experimental data are briefly discussed.
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Keywords: Nanotwinned materials, plastic deformation, yield strength, fracture, cracks, defects, modeling
Pages: 204-212
WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 10, 2015, Art. #22