Size-dependent plastic deformation of twinned nanopillars in body-centered cubic tungsten

2017 ◽  
Vol 121 (17) ◽  
pp. 175101 ◽  
Author(s):  
Shuozhi Xu ◽  
Jacob K. Startt ◽  
Thomas G. Payne ◽  
Chaitanya S. Deo ◽  
David L. McDowell
2004 ◽  
Vol 52 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Tong-Yi Zhang ◽  
Wei-Hua Xu ◽  
Ming-Hao Zhao

2020 ◽  
Vol 87 (11) ◽  
Author(s):  
Gurudas Kar ◽  
Debasish Roy ◽  
J. N. Reddy

Abstract In this work, we develop a thermo-viscoplasticity model for body-centered cubic (BCC) metals based on a two-temperature theory of nonequilibrium thermodynamics. Modeling the plastic deformation here involves two subsystems, viz., a configurational subsystem related to grain growth, dislocation motion, and a kinetic vibrational subsystem describing the vibration of atoms. Due to a separation of the time scales, the two subsystems are described by two different temperatures. In this study, we introduce a grain boundary density, in addition to the mobile and forest dislocation densities, as an internal variable. The focus in this paper is on how large plastic deformation is affected by the evolving grain boundaries. In order to check the predictive quality of the model, numerical simulations are conducted and validated against available experimental evidence wherever possible.


2009 ◽  
Vol 105 (8) ◽  
pp. 083521 ◽  
Author(s):  
Z. H. Cao ◽  
H. M. Lu ◽  
X. K. Meng ◽  
A. H. W. Ngan

2010 ◽  
Vol 20 (7) ◽  
pp. 1021-1048 ◽  
Author(s):  
J.W. Ju ◽  
K. Yanase

A size-dependent micromechanical framework is proposed to predict the deformation responses of particle-reinforced metal matrix composites by incorporating the essential features of the dislocation plasticity. Within the framework of probabilistic micromechanical formulation, the damage caused by the manufacturing process and by the external mechanical loading in the presence of thermal residual stresses is considered. The effective elastic moduli of four-phase composites, consisting of a ductile matrix and randomly located spherical intact or damaged particles are derived. Subsequently, the size-dependent plastic deformation behavior of particle-reinforced metal matrix composites is predicted with a dislocation theory. Specifically, the density of dislocations due to the thermal contraction misfit and the plastic deformation misfit is taken into consideration within the micromechanical methodology to account for the dislocation strengthening. To predict the overall elastoplastic damage behavior of composites, a size-dependent hybrid effective yield function is presented on the basis of the ensemble-volume averaging and the modified matrix yield strength. The comparisons between our predictions and available experimental data illustrate the potential capability of the proposed framework. Numerical simulations are also performed to exhibit the salient features of the proposed methodology.


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