Impact of non-Schmid stress components present in the yield criterion for bcc metals on the activity of {110}<111> slip systems

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F19%3A00498668" target="_blank" >RIV/68081723:_____/19:00498668 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0927025618308000?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0927025618308000?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.commatsci.2018.12.021" target="_blank" >10.1016/j.commatsci.2018.12.021</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Impact of non-Schmid stress components present in the yield criterion for bcc metals on the activity of {110}<111> slip systems

Popis výsledku v původním jazyce

It has been found in a number of computer simulations that the yield criterion for the onset of crystal plasticity ofnbody-centered cubic (bcc) metals generally involves stress components other than the shear stress parallel to thenslip direction. This is a consequence of the non-planar cores of 1/2<111> screw dislocations that control the plastic deformation of bcc crystals. The significance of these non-Schmid stress components differs from material to material and thus their contributions to the yield criterion requires either extensive atomistic simulations ofnisolated 1/2[111] screw dislocations or their estimates from experiments. In this paper, we derive a set of con-nstraints imposed on the parameters of the yield criterion that control the importance of different stress com-nponents so that the orientation dependence of the critical resolved shear stress and its dependence on the shearnstress perpendicular to the slip direction have trends agreeing with atomistic computer simulations. Using thenallowed combinations of these parameters, we identify the primary and secondary {110}<111> slip systems fornloadings in tension and compression along three specifically oriented loading axes within the standard stereo-ngraphic triangle. In this context we show that the origin of the tension-compression asymmetry is not relatednpurely to the well-known twinning-antitwinning asymmetry of the yield stress but to a combination of thisnasymmetry with the effect of the shear stresses perpendicular to the slip direction. Additionally, we demonstratenthat our yield criterion, which is based only on the shear stresses parallel and perpendicular to the slip direction,nis fully equivalent to more complex yield criteria that contain explicit dependences on normal stresses per-npendicular and parallel to the dislocation line. These additional stress terms are shown to emerge due to pro-njection of the applied stress tensor into an orthogonal basis that does not conform with the three-fold screwnsymmetry of the <111> rotation axis implicit in bcc crystal structures.n

Název v anglickém jazyce

Impact of non-Schmid stress components present in the yield criterion for bcc metals on the activity of {110}<111> slip systems

Popis výsledku anglicky

It has been found in a number of computer simulations that the yield criterion for the onset of crystal plasticity ofnbody-centered cubic (bcc) metals generally involves stress components other than the shear stress parallel to thenslip direction. This is a consequence of the non-planar cores of 1/2<111> screw dislocations that control the plastic deformation of bcc crystals. The significance of these non-Schmid stress components differs from material to material and thus their contributions to the yield criterion requires either extensive atomistic simulations ofnisolated 1/2[111] screw dislocations or their estimates from experiments. In this paper, we derive a set of con-nstraints imposed on the parameters of the yield criterion that control the importance of different stress com-nponents so that the orientation dependence of the critical resolved shear stress and its dependence on the shearnstress perpendicular to the slip direction have trends agreeing with atomistic computer simulations. Using thenallowed combinations of these parameters, we identify the primary and secondary {110}<111> slip systems fornloadings in tension and compression along three specifically oriented loading axes within the standard stereo-ngraphic triangle. In this context we show that the origin of the tension-compression asymmetry is not relatednpurely to the well-known twinning-antitwinning asymmetry of the yield stress but to a combination of thisnasymmetry with the effect of the shear stresses perpendicular to the slip direction. Additionally, we demonstratenthat our yield criterion, which is based only on the shear stresses parallel and perpendicular to the slip direction,nis fully equivalent to more complex yield criteria that contain explicit dependences on normal stresses per-npendicular and parallel to the dislocation line. These additional stress terms are shown to emerge due to pro-njection of the applied stress tensor into an orthogonal basis that does not conform with the three-fold screwnsymmetry of the <111> rotation axis implicit in bcc crystal structures.n

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Computational Materials Science

ISSN

0927-0256

e-ISSN

—

Svazek periodika

159

Číslo periodika v rámci svazku

MAR

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

9

Strana od-do

297-305

Kód UT WoS článku

000457856900029

EID výsledku v databázi Scopus

2-s2.0-85058694788