A modified model for deformation via partial dislocations and stacking faults at the nanoscale
نویسندگان
چکیده
The partial dislocation model for the deformation mechanism of nanocrystalline materials is extended to consider the influence of non-uniform dislocation extension. The non-uniform partial dislocation extension model is more consistent with experimental data than the original partial dislocation model. Additionally, the flow stress obtained from the non-uniform extension model is compared with that from the Hall–Petch relation. 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
منابع مشابه
Investigation of extended stacking fault emission from grain boundaries using a density functional theory -informed 3D phase field dislocation dynamics model
As characteristic length scales shrink (<100 nm) in fcc metals, alternative deformation mechanisms not seen in bulk and course-grained material counterparts emerge. In particular in grain sizes on the order of 10s of nanometers, plasticity is mediated by the motion and interaction of partial dislocations and extended stacking faults. Typically, partial dislocations nucleate at grain boundary de...
متن کاملCharacterizing faulted dipoles in TiAl with electron microscopy and computed image simulations
The low temperature deformation microstructure of TiAl is dominated by the presence of stacking fault dipoles [I]. Two different faulted dipole geometries have been proposed in the literature [2,3], and the existence of both types of faulted dipoles have been verified in the present study with comparisons to computer simulated images. These comparisons suggest that extrinsic stacking faults in ...
متن کاملMolecular Dynamics Simulation on Plastic Deformation of Metallic Nanowires
We have studied the initial stage of plastic deformation behavior of metallic nanowire of pure nickel, by using molecular dynamics methods. In these simulations, we applied uniform strain along c-axis at strain rate of 0.5%/100ps, 0.5%/10ps and 0.1%/2ps. We have observed the formation of stacking faults by movement of a partial dislocation, and the development of stacking faults to deformation ...
متن کاملAtomic-scale dynamic process of deformation-induced stacking fault tetrahedra in gold nanocrystals.
Stacking fault tetrahedra, the three-dimensional crystalline defects bounded by stacking faults and stair-rod dislocations, are often observed in quenched or irradiated face-centred cubic metals and alloys. All of the stacking fault tetrahedra experimentally observed to date are believed to originate from vacancies. Here we report, in contrast to the classical vacancy-originated ones, a new kin...
متن کاملStable Stacking Faults Bounded by Frank Partial Dislocations in Al7075 Formed through Precipitate and Dislocation Interactions
Through high-resolution electron microscopy, stacking faults (SFs) due to Frank partial dislocations were found in an aluminum alloy following deformation with low strain and strain rate, while also remaining stable during artificial aging. Extrinsic stacking faults were found surrounded by dislocation areas and precipitates. An intrinsic stacking fault was found between two Guinier-Preston II ...
متن کامل