Nucleation of twins and dislocations in V-Ti alloys under various straining conditions

Aleksandr Korchuganov,Dmitrij Kryzhevich,Konstantin Zolnikov,V Fomin,L Placidi

doi:10.1051/epjconf/201922101023

Abstract

The features of plasticity nucleation in V-4Ti and V-16Ti crystallites under uniaxial tension and bilateral compression are studied. It is shown that the nucleation of plasticity in crystallites is associated with the formation of twins under uniaxial tension. During the development of plasticity, a screw dislocation cell structure is formed between twin plates. The strain and stress at which plasticity nucleates in the material decreases with increasing Ti concentration. It was found that the distribution pattern of Ti atoms in the initial structure has a significant effect on the elastic limit of the simulated crystallites. The plastic deformation of crystallites with 16% Ti under bilateral compression is realized only by the dislocation mechanism. This behavior of the material is due to the low value of the stress at the elastic limit, which is insufficient for the formation of twins.

Highlights

Along with low-activation ferritic-martensitic steels [1,2,3], vanadium-based alloys are promising structural materials in the nuclear power industry [4, 5]
Molecular dynamics simulation showed that the nucleation of plastic deformation under uniaxial tension of crystallites V-4Ti and V-16Ti is realized by twinning
Screw dislocations are generated in the stretched crystallites during the growth of twins

Summary

Introduction

Along with low-activation ferritic-martensitic steels [1,2,3], vanadium-based alloys are promising structural materials in the nuclear power industry [4, 5]. The results of simulation of the behavior of nanoscale iron single crystals are undoubtedly useful in studying V-Ti alloys both in terms of similarity and differences in the behavior of materials with a bcc structure. It should be taken into account that the properties and peculiarities of plasticity nucleation differ significantly for nanoscale crystallites and bulk single crystals [24, 25]. This is due to the increasing contribution from free surfaces to the deformation process. The mechanisms of plasticity nucleation in nanoscale bcc V-Ti single crystals with a different stoichiometric composition for various schemes of high-rate mechanical loading have been studied on the basis of molecular dynamics simulation

Methods

Uniaxial tension

Loading in confined conditions

Findings

Conclusions