Ab Initio Molecular Dynamics Study of the Structure and Properties of Nb-Doped Zr-Cu-Al Amorphous Alloys

Round 1

Reviewer 1 Report

The Zr-based bulk metallic glasses were investigated for more than 30 years. However, no significant results for the practical application of such materials have not been shown. And hardly may be shown due to small critical diameter and lack of tensile plasticity at room temperature. These facts do not let to use these materials as constructional. So, the topic presented by the authors is not actual. The authors of the paper “Ab Initio Molecular Dynamics Study of the Structure and Properties of Nb-doped Zr-Cu-Al Amorphous Alloys” in the introduction part should explain the potential application of such specific materials as Zr-based bulk metallic glasses.

Despite the not actual material chosen for research, the authors have made a good theoretical work. The obtained results are interesting from a scientific point of view. The paper may be accepted for publication after correction accordingly following comments:

1. The introduction part should be significantly improved:

• More last references about Zr-based BMGs should be analysed;
• The last references devoted to Zr-based BMGs should be considered in view of the potential application of such materials.
• The stress-strain curves presented by the authors in the Introduction part should be moved to the Results part and described in more detail.

2. The details of the samples preparation process for compression tests (melting, casting conditions etc.) and the description of the compression tests (strain rate, size of the samples etc.) should be described in the Materials and Methods part.
3. The authors should compare obtained distribution of atoms in clusters with Miracle’s model of the metallic glass atomic structure (doi:10.1038/nmat1219).

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper contains important data and can be published subject to amendments to account for the followings:

1. No data are given on glass transition temperatures of systems investigated.
2. The introductory part is clearly missing important overview information on mechanical behaviour of glasses, for example the recent overview “Mechanical Properties and Deformation Behavior of Bulk Metallic Glasses”, Metals 2013, 3, 1-22; doi:10.3390/met3010001 might be a complementary source of insight into the paper topic. Concerning Chapter 3.3: it is notable that recently A. Tlahuice-Flores et al as well as R.F. Tournier et all investigated bonding systems, see e.g. “Bonding and properties of superatoms. Analogs to atoms and molecules and related concepts from superatomic clusters”. Quantum Chem. 2019, 119, e25756 and “Building and breaking bonds by homogenous nucleation in glass-forming melts leading to three liquid states”. Materials 2021, 14, 2287, doi:10.3390/ma14092287 which are not noted anywhere.
3. Additionally, the paper deals with MD simulation (computer experiment) whereas Figure 1 seems to be a laboratory test result. Because of that it needs a much more detailed explanation of experimental conditions, materials etc as well as a relevant reference if the results presented in this figure are already published elsewhere.
4. Lines 50-51 specify that “this problem was studied in this paper in combination with the experimental results and ab initio molecular dynamics (AIMD) simulation…”. If the experimental results are involved, then they have to be also described within the following chapters of manuscript. Currently there is only present the Chapter 2 on simulation.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have answered the previous comments and made necessary modifications to the manuscript. In my opinion, the paper may be accepted for publication.

Reviewer 2 Report

Accept