Investigating Nanoscale Contact Using AFM-Based Indentation and Molecular Dynamics Simulations

Round 1

Reviewer 1 Report

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Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Corrections of typos and suggestions for minor text modifications

• Line 5: “be smaller than” (instead of “be less than”)
• Lines 7-9: suggestion for text modification: “Increasing the temperature of the simulations accelerates the rate of thermally activated processes and promotes motion and annihilation of dislocations under the indent while transferring material to the upper surface; dislocation density decreases in the plastic zone and material piles-up around the indent.”
• Line 34: “the indentation size effect” (eliminate 3)
• Line 34: “They” (instead of “The”)
• Lines 58-59: The sentence “Although the plastic zone …is expected” is not understandable”; for me it is redundant
• Line 81: “…cross-sections show…” (instead of “shows”)
• Line 87: please, provide the AFM tip radius
• Line 95: Please provide information about the MD simulation of the virtual indenter: is it rigid of is modelled at atomic scale; and in that case which is the material and potential employed
• Lines 98-100: Please state that the MD relaxation and indentation steps are performed at 10 K (it is mentioned later in the text, but it should be made clear here)
• Lines 106-107: Sentence difficult to understand. The end of it, “by the the internal stresses…relax”, is not clear for me.
• Caption fig. 2, second line: 200 nm (instead of 200 mm)
• , last line: change proposed, “the initial plastic response…”
• Line 224: “The Burgers vector of all dislocations is parallel…”
• Caption fig. 7, first and second lines: suggestion for change, “The total dislocation length has been calculated by adding the length of perfect dislocations to half the length of partial dislocations.”
• Line 338: “after the films” instead of “after they films”
• Line 482: suggested addition, “…that AFM indentation (i.e., very shallow indentation)…”

General remarks

1. ¿Could they comment why they have opted in their MD simulations by indenting at 10 K (i.e., practically athermal conditions) and then relaxing the internal stresses at higher temperatures instead of indenting at different higher temperatures and then unloading by retiring the indenter? They should, at least, tried to do so. I have the impression that this is a weakness of this paper.
2. Their final proposal (lines 497-500) seems a too obvious one.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

This work investigates the dislocation dynamics in Au films upon AFM-based indentation and MD simulation. The paper gives a good impression. It is well organized and logically written, in a high-quality technical language. I have suggestions only for minor improvements of the manuscript.

1. Please add a sentence stating the goal of this work in the Abstract. This will help a broad audience of readers grasp the significance of the presented data.
2. Please explain abbreviations AFM and TEM in the Abstract.
3. In the manuscript, please explain the choice of gold as the material of the film.
4. The Authors propose that "closely spaced pinning sites ... might be able to hinder the annihilation of dislocations". What are the perspectives of ceramic particles for playing the role of these sites? Can experimental results be obtained for clarifying that?

Author Response

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Author Response File: Author Response.pdf