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| The Effect of Dislocation Stacking Under Uniaxial Tension on Microcrack Growth in Metallic Crystals |
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Abstract Abstract:TFor nanocrystalline materials, the interaction between cracks in nanocrystalline aluminum and slip surfaces formed by dislocations emitted from crack tips under uniaxial tensile loading is studied.By using the distributed dislocation method, the crack and slip surface are equivalent to the uniformly distributed continuous dislocation, and the stress field on the crack surface is obtained.The effect of dislocation free zone on the initiation and propagation of the microcrack is studied by introducing the dislocation free zone at the crack tip.The results show that the crack length is short without considering the dislocation free zone at the crack tip, and the microcracks will be formed at the grain boundary first, and the main crack will directly penetrate the crystal when the main crack is longer. When the angle between slip surface and crack tip is large, the number of dislocations emitted at the crack tip will be increased, thus inhibiting the propagation of main crack.When the dislocation free zone at the crack tip is considered, the microcracks appear in the dislocation free zone prior to the grain boundary. The mutual emission of dislocations between the main crack and the microcracks leads to the convergence of the crack and the microcracks at the crack tip, which effectively accelerates the propagation of the main crack.
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Received: 18 March 2021
Published: 19 April 2022
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| Fund:national natural science foundation of china |
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2022, Vol. 43 
