Simulation and Experimental Study on the Inhomogeneity of Mechanical Properties of Aluminum Alloy 7050 Plate

Round 1

Reviewer 1 Report

I have some comments to the manuscript (767694) as follows;

1. P1 Abstract line 4 from above: “the homogeneity” should be “the inhomogeneity”.
2. P2 line 13 from bottom: You write “Using the Deform software, a finite element model --------”. Please mention the name of these software and the developer.
3. P3 equation (10): You write flow stress by equation (10) which is one side of rolling condition. Same time, the total strain ε is also important to simulate the grain size. Please add the author’s opinion about strain itself.
4. P4 line17 form bottom: You write “The hot compression tests were conducted on Gleeble-3180 ----”. Please draw the shape and the size of the test specimen.
5. P5 line 4 form above: You write suddenly “The simulation result of grain size distribution of the Al alloy plate was shown in Figure 2”. I suppose the software has simulation steps, like calculation step of the temperature, the strain rate, the stress-strain curve, the recovery, the recrystallization and finally the grain size. Please show the flowchart of simulation steps.
6. Figure 2(a): I cannot see well the color bar of grain size. Please show clearer.
7. Figure 2(b): You had better compare the simulation and the experimental three grain size values in this figure not only write in the text.
8. Figure 3(a), (b) and (c) need the symbols of S, Q and H correspondingly.
9. Figure 3(c): When I observe the Figure 3, the microstructure is the mixture of fine grain lower than 20μm and extremely course grain. You mentioned the mean value of 67.97μ I doubt the grain size distributions are separate to two with the median like 20 and 100μm respectively, for example. Separation of the two distribution means there is no grain correspond to the size of 67.97μm. Please check the distribution of the grain size of (c). If the size is normal single Gaussian distribution, there is no problem.
10. Figure 7: This is actual yield stress data. You had better compere between the simulated yield data and experimental data in this figure not only in text. Because, reader confuse the data is simulation of accrual.
11. Line 11-24; You divided into three stages Ⅰ, Ⅱ and Ⅲ. Please indicate these three stages schematically in Figure 5(b).

That’s the end of my comments.

Author Response

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Reviewer 2 Report

Recommendations:

• syntesis of the abstract, is too long;
• at introduction, introduce a few paragraphs;
• at conclusions, comparing the obtained results (inhomogeneity and error) with the specialized literature and divide that two conclusions in more (3 or 4);
• at references, some new bibliographic notes can be added.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Review metals-767694

After careful analysis of the paper entitled “Simulation and Experimental Study on the Inhomogeneity of Mechanic Properties of Aluminium Alloy 7050 Plate”, the reviewer considers the subject to be of interest, but the authors’ approach is not concise enough and can be interpreted in different manners, depending on the reader. The following brief aspects can lead to the rejection of the paper from Metals journal:

• In the title, the proper term is mechanical properties, not mechanic properties.
• The abstract should focus on the simulations (describing the simulations), experiments (describing the experiment and characterisation) and findings (briefly present best results) of the paper.
• The keywords are too general and should be improved to better represent the paper.
• English & spelling should be thoroughly checked throughout the manuscript. It is highly recommended that a native English speaker checks the paper. In all languages, the sentences start with a Capital Letter.
• There are numerous incorrect or incomplete expressions (e.g. “The main purpose of rolling is to improve the mechanical properties of the alloy and reduce or eliminate casting defects.”). The main aspect of rolling deformation, in this case, is not presented. For a brief documentation, there are a number of didactic works available.
• In the main part of the introduction, a lot of information related to Mg alloys is presented, with very little connection to the alloy studied in this work. For a work to be considered of high-quality, the material classes must not be confused with each other, even if globally they contain the same chemical elements. The elemental proportion is the main characteristic leading to different properties, besides the processing methods post-synthesis. The vaguest relation presented was to Alloy 7050. The reviewer would like to remind the authors the literature regarding alloy 7050 is abundant.
• Regarding the FEM modelling, the authors have tried to obtain some results more on an intuitive basis instead of existing works. This impression was generated, first of all, from the initial assumptions of the authors. It is well known that rolling deformation is a tridimensional process, each dimensional component having its own importance. Even for low deformations, the rolling deformation cannot be simplified as a plane strain problem and ignore the spread in direction of width.
• Mathematical models used for heat transfer and flow stress should not be presented, as they are completely reproduced from other works. Therefore, a brief description and the proper citation suffice, if no novel elements are introduced.
• In the experimental section, such as, “The samples were taken from different thickness layers: top surface layer(S), 1/4 layer (Q) and 1/2 layer (H), and were made into cylinders of size Φ10mm×15mm” with roughness parameters Ra 1.6 and Ra 0.8. The method through which these roughness parameters were obtained is not presented. The number of samples extracted and tested should be mention, as well as the distance between extraction areas, in relation to figure 2b. The process through which the samples were obtained as cylinders from the cast ingot should be included, as well. Otherwise, where is the experimental component of the work?
• On what basis were the following temperatures chosen: 30, 150, 250, 350 and 450 °C chose? Are they related to phase diagrams? Please state this in the text.
• References section should be formatted according to the journal’s requirements.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The authors have addressed all of my initial comments. I agree that the difference between 2D and 3D simulations will not substantially influence the results, however this needed to be stated in the text.

The title, keywords, introduction, experimental, simulation and conclusions sections have been thoroughly revised and updated. They are now of an adequate level for Metals.

However, English Language is still unsatisfactory and needs to be thoroughly revised. This necessarily needs to be addressed before publication.

Author Response

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Author Response File: Author Response.pdf