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

Result code in 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>

Result on the web

<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>

Result language

angličtina

Original language name

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

Original language description

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.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

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

Project

—

Continuities

O - Projekt operacniho programu

Publication year

2017

Confidentiality

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

Name of the periodical

ACTA MATERIALIA

ISSN

1359-6454

e-ISSN

—

Volume of the periodical

125

Issue of the periodical within the volume

15 February 2017

Country of publishing house

GB - UNITED KINGDOM

Number of pages

11

Pages from-to

431-441

UT code for WoS article

000394201500043

EID of the result in the Scopus database

2-s2.0-85006819087