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

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• 作者：Zhibo Zhang^a ; Alexander Stukowski^b ; Herbert M. Urbassek^a ; ^{urbassek@rhrk.uni-kl.de" class="auth_mail" title="E-mail the corresponding author} ;
• 关键词：Atomistic simulation ; Silicon ; Phase transformation ; Dislocations ; Stacking faults ; Amorphization
• 刊名：Computational Materials Science
• 出版年：2016
• 出版时间：15 June 2016
• 年：2016
• 卷：119
• 期：Complete
• 页码：82-89
• 全文大小：4370 K

文摘

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 $\frac{1}{4}〈111〉$ and $\frac{1}{3}〈112〉$ are discussed.