Unraveling deformation mechanisms around FCC and BCC nanocontacts through slip trace and pileup topography analyses

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23640%2F17%3A43931746" target="_blank" >RIV/49777513:23640/17:43931746 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.actamat.2016.11.067" target="_blank" >http://dx.doi.org/10.1016/j.actamat.2016.11.067</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.actamat.2016.11.067" target="_blank" >10.1016/j.actamat.2016.11.067</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Unraveling deformation mechanisms around FCC and BCC nanocontacts through slip trace and pileup topography analyses

Popis výsledku v původním jazyce

Nanocontact loadings offer the potential to investigate crystal plasticity from surface slip trace emissions and distinct pileup patterns where individual atomic terraces arrange into hillocks and symmetric rosettes. Our MD simulations in FCC Cu and Al nanocontacts show development of specific dislocation interception, cross-slip and twin annihilation mechanisms producing traces along characteristic &lt;011&gt; and &lt;112&gt; directions. Although planar slip is stabilized through subsurface dislocation interactions, highly serrated slip traces always predominate in Al due to the advent of cross-slip of the surfaced population of screw dislocations, leading to intricate hillock morphologies. We show that the distinct wavy hillocks and terraces in BCC Ta and Fe nanocontacts are due to dislocation kinking and outward spreading of surfaced screw segments, which originate from dislocation loops induced by twin annihilation and twin-mediated nucleation processes in the subsurface. While increasing temperature favors terrace formation in BCCs, surface decorations are enhanced in FCCs limiting hillock definition. It is found that material bulging against the indenter-tip is a distinctive feature in nanocontact plasticity associated with intermittent defect bursts. Bulging is enhanced by recurrent slip traces introduced throughout the contact surface, as in the case of the strongly linear defect networks in FCC Al, and by specific twin arrangements at the vicinity of BCC nanocontacts. Defect patterning also produces surface depressions in the form of vertexes around FCC nanoimprints. While the rosette morphologies are consistent with those assessed experimentally in greater FCC and BCC imprints, topographical pileup due to extensive bulging becomes prominent at the nanoscale.

Název v anglickém jazyce

Unraveling deformation mechanisms around FCC and BCC nanocontacts through slip trace and pileup topography analyses

Popis výsledku anglicky

Nanocontact loadings offer the potential to investigate crystal plasticity from surface slip trace emissions and distinct pileup patterns where individual atomic terraces arrange into hillocks and symmetric rosettes. Our MD simulations in FCC Cu and Al nanocontacts show development of specific dislocation interception, cross-slip and twin annihilation mechanisms producing traces along characteristic &lt;011&gt; and &lt;112&gt; directions. Although planar slip is stabilized through subsurface dislocation interactions, highly serrated slip traces always predominate in Al due to the advent of cross-slip of the surfaced population of screw dislocations, leading to intricate hillock morphologies. We show that the distinct wavy hillocks and terraces in BCC Ta and Fe nanocontacts are due to dislocation kinking and outward spreading of surfaced screw segments, which originate from dislocation loops induced by twin annihilation and twin-mediated nucleation processes in the subsurface. While increasing temperature favors terrace formation in BCCs, surface decorations are enhanced in FCCs limiting hillock definition. It is found that material bulging against the indenter-tip is a distinctive feature in nanocontact plasticity associated with intermittent defect bursts. Bulging is enhanced by recurrent slip traces introduced throughout the contact surface, as in the case of the strongly linear defect networks in FCC Al, and by specific twin arrangements at the vicinity of BCC nanocontacts. Defect patterning also produces surface depressions in the form of vertexes around FCC nanoimprints. While the rosette morphologies are consistent with those assessed experimentally in greater FCC and BCC imprints, topographical pileup due to extensive bulging becomes prominent at the nanoscale.

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

—

Návaznosti

O - Projekt operacniho programu

Rok uplatnění

2017

Kód důvěrnosti údajů

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

Název periodika

ACTA MATERIALIA

ISSN

1359-6454

e-ISSN

—

Svazek periodika

125

Číslo periodika v rámci svazku

15 February 2017

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

11

Strana od-do

431-441

Kód UT WoS článku

000394201500043

EID výsledku v databázi Scopus

2-s2.0-85006819087