Explicit incorporation of cross-slip in a dislocation density-based crystal plasticity model

Author(s):  
Alankar Alankar ◽  
David P. Field ◽  
Hussein M. Zbib
2009 ◽  
Vol 57 (19) ◽  
pp. 5936-5946 ◽  
Author(s):  
Alankar Alankar ◽  
Ioannis N. Mastorakos ◽  
David P. Field

Author(s):  
Stephanie A Pitts ◽  
Wen Jiang ◽  
Davide Pizzocri ◽  
Erin I. Barker ◽  
Hussein Zbib

Abstract Radiation-induced embrittlement of reactor pressure vessel (RPV) steels can potentially limit the operating life of nuclear power plants. Over extended exposure to radiation doses, these body-centered cubic (BCC) irons demonstrate irradiation damage. Here, we present a continuum dislocation density (CDD) crystal plasticity model to capture the interaction among dislocations and self-interstitial atom (SIA) loops in α-iron. We demonstrate the importance of modeling cross slip using a combined stochastic Monte Carlo approach and the role of slip system strength anisotropy in capturing stochastic cross slip interactions. Through these captured interactions, the CDD crystal plasticity model can capture both the stress response and the physical evolution of dislocation on different slip system planes. Single-crystal verification experiments are used to calibrate the CDD crystal plasticity model, and a set of simplified polycrystalline simulations demonstrates the model's ability to capture the stress response from tensile experiments on α-iron.


2021 ◽  
Vol 7 ◽  
Author(s):  
Jan E. Schnabel ◽  
Ingo Scheider

A crystal plasticity model of the creep behavior of alloys with lamellar microstructures is presented. The model is based on the additive decomposition of the plastic strain into a part that describes the instantaneous (i.e., high strain rate) plastic response due to loading above the yield point, and a part that captures the viscoplastic deformation at elevated temperatures. In order to reproduce the transition from the primary to the secondary creep stage in a physically meaningful way, the competition between work hardening and recovery is modeled in terms of the evolving dislocation density. The evolution model for the dislocation density is designed to account for the significantly different free path lengths of slip systems in lamellar microstructures depending on their orientation with respect to the lamella interface. The established model is applied to reproduce and critically discuss experimental findings on the creep behavior of polysynthetically twinned TiAl crystals. Although the presented crystal plasticity model is designed with the creep behavior of fully lamellar TiAl in mind, it is by no means limited to these specific alloys. The constitutive model and many of the discussed assumptions also apply to the creep behavior of other crystalline materials with lamellar microstructures.


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