Open AccessSelf‐Healing and Shape Memory Effects in Gold Microparticles through the Defects‐Mediated Diffusion
Author(s) -
Kovalenko Oleg,
Brandl Christian,
Klinger Leonid,
Rabkin Eugen
Publication year - 2017
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201700159
Subject(s) - materials science , annealing (glass) , shape memory alloy , indentation , diffusion , work (physics) , deformation (meteorology) , metal , atomic diffusion , composite material , nanotechnology , chemical physics , crystallography , metallurgy , thermodynamics , chemistry , physics
Some metal alloys subjected to irreversible plastic deformation can repair the inflicted damage and/or recover their original shape upon heating. The conventional shape memory effect in metallic alloys relies on collective, or “military” phase transformations. This work demonstrates a new and fundamentally different type of self‐healing and shape memory in single crystalline faceted nano and microparticles of pure gold, which are plastically deformed with an atomic force microscope tip. It is shown that annealing of the deformed particles at elevated temperatures leads to nearly full recovery of their initial asymmetric polyhedral shape, which does not correspond to global energy minimum shape. The atomistic molecular dynamic simulations demonstrate that the shape recovery of the particles is controlled by the self‐diffusion of gold atoms along the terrace ledges formed during the particles indentation. This ledge‐guided diffusion leads to shape recovery by the irreversible diffusion process. A semiquantitative model of healing developed in this work demonstrates a good agreement with the experimental data.