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dc.contributor.authorVarillas Delgado, Javier
dc.contributor.authorOcenásek, Jan
dc.contributor.authorTorner Ribé, Jordi
dc.contributor.authorAlcalá Cabrelles, Jorge
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament d'Expressió Gràfica a l'Enginyeria
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament de Ciència dels Materials i Enginyeria Metal·lúrgica
dc.identifier.citationVarillas, J., Ocenásek, J., Jordi Torner, Alcala, J. Unraveling deformation mechanisms around FCC and BCC nanocontacts through slip trace and pileup topography analyses. "Acta materialia", 15 Febrer 2017, vol. 125, p. 431-441.
dc.description.abstractNanocontact 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 <011> and <112> 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 double-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. Increasing temperature favors terrace formation in BCCs whereas the enhancement of surface decorations in FCCs limits 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, local bulging promoted during tip removal becomes more prominent at the nanoscale.
dc.format.extent11 p.
dc.subjectÀrees temàtiques de la UPC::Enginyeria dels materials
dc.subject.lcshNanostructured materials
dc.subject.otherSlip traces
dc.subject.otherIndentation pileup
dc.subject.otherIndentation rosettes
dc.titleUnraveling deformation mechanisms around FCC and BCC nanocontacts through slip trace and pileup topography analyses
dc.subject.lemacMaterials nanoestructurats
dc.contributor.groupUniversitat Politècnica de Catalunya. InSup - Grup de Recerca en Interacció de Superfícies en Bioenginyeria i Ciència dels Materials
dc.description.peerreviewedPeer Reviewed
dc.rights.accessOpen Access
dc.description.versionPostprint (author's final draft)
upcommons.citation.authorVarillas, J.; Ocenásek, J.; Torner, Jordi; Alcala, J.
upcommons.citation.publicationNameActa materialia

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