Investigation of loading orientation effect on dynamic deformation of single crystal copper at high strain rates: Discrete dislocation dynamics study
(English)Manuscript (preprint) (Other academic)
Uniaxial tensile loading of copper single crystal along  and  orientations is modeled at two high strain rates of 105 and 106 s-1. Discrete dislocation dynamics method is used to study the anisotropic characteristic of plastic deformation in the model crystal. Furthermore, strain rate sensitivity of the flow stress in copper crystal is examined. Investigation of mechanical response of single crystal to the external loading demonstrates a substantial effect of loading orientation on the plastic flow. We find that at both imposed strain rates flow stress increases significantly when tensile load is applied along  crystallographic axis. Similarly, plastic anisotropy is observed in dislocation density evolution such that more dislocations are generated as straining direction of single crystal is changed from  to  axis. Moreover, plastic flow behavior exhibits a profound strain rate sensitivity at both loading orientations which agrees well with experimental observations regarding strain rate dependency of flow stress in copper single crystal as strain rate exceeds 103 s-1. At both applied strain rates dislocations evolve into a heterogeneous microstructure and highest heterogeneity is observed as model crystal is loaded along  direction at strain rate of 106 s-1. Formation of slip bands and consequently localization of plastic deformation are detected for all considered cases. However, at the higher strain rate of 106 s-1, slip band formation is more pronounced for both loading orientations.
Discrete dislocation dynamics, Crystal plasticity, Plastic anisotropy, Cu single crystal, High strain rate deformation, Slip band formation
Materials Engineering Metallurgy and Metallic Materials
Research subject Materials Science and Engineering
IdentifiersURN: urn:nbn:se:kth:diva-175414OAI: oai:DiVA.org:kth-175414DiVA: diva2:860850
QS 20152015-10-142015-10-142015-10-14Bibliographically approved