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Interplay of dislocation-based plasticity and phase transformation during Si nanoindentation

Zhang, Zhibo and Stukowski, Alexander and Urbassek, Herbert M. (2016):
Interplay of dislocation-based plasticity and phase transformation during Si nanoindentation.
In: Computational Materials Science, pp. 82-89, 119, ISSN 09270256,
[Online-Edition: http://dx.doi.org/10.1016/j.commatsci.2016.03.039],
[Article]

Abstract

Nanoindentation into single-crystalline Si is modeled by molecular dynamics simulation using a modified Tersoff potential. We observe that the high stress produced during indentation leads to three processes occurring consecutively in the substrate: (i) phase transformation of the original cubic diamond (cd) to the bct5 phase; (ii) generation of dislocations; and (iii) amorphization. The bct5 phase develops along {1 1 1} planes of the cd phase; when these meet, the enclosed volume of cd phase transforms to bct5. The particular role played by a stable tetrahedral structure formed by bct5 {1 1 1} planes and {1 1 1} intrinsic stacking faults in the cd structure is highlighted. The phase transformation to bct5 is partially reversed when dislocations nucleate in the cd phase and locally relieve stresses. The generation and reactions of the uncommon dislocations 1/4 〈111〉 and 1/3 〈112〉 are discussed.

Item Type: Article
Erschienen: 2016
Creators: Zhang, Zhibo and Stukowski, Alexander and Urbassek, Herbert M.
Title: Interplay of dislocation-based plasticity and phase transformation during Si nanoindentation
Language: English
Abstract:

Nanoindentation into single-crystalline Si is modeled by molecular dynamics simulation using a modified Tersoff potential. We observe that the high stress produced during indentation leads to three processes occurring consecutively in the substrate: (i) phase transformation of the original cubic diamond (cd) to the bct5 phase; (ii) generation of dislocations; and (iii) amorphization. The bct5 phase develops along {1 1 1} planes of the cd phase; when these meet, the enclosed volume of cd phase transforms to bct5. The particular role played by a stable tetrahedral structure formed by bct5 {1 1 1} planes and {1 1 1} intrinsic stacking faults in the cd structure is highlighted. The phase transformation to bct5 is partially reversed when dislocations nucleate in the cd phase and locally relieve stresses. The generation and reactions of the uncommon dislocations 1/4 〈111〉 and 1/3 〈112〉 are discussed.

Journal or Publication Title: Computational Materials Science
Volume: 119
Uncontrolled Keywords: Atomistic simulation; Silicon;Phase transformation;Dislocations; Stacking faults;Amorphization
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 28 Apr 2016 09:35
Official URL: http://dx.doi.org/10.1016/j.commatsci.2016.03.039
Identification Number: doi:10.1016/j.commatsci.2016.03.039
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