Effect of Al Content on the Microstructural and Grain Growth Kinetics of Magnesium Alloys

Round 1

Reviewer 1 Report

This is a good work on materials science.  

As a comment, the following might be mentioned: It is not at all clear how the authors calculate the grain size. They note that "The grain size measurements were performed according to the Nano Measurer software." I note that, without an additional explanation, the phrase "the size of grains" does not mean anything to the reader. Let me explain. In the case of spherical grains, the size might be interpreted as the diameter of a sphere. However, the shape of the presented images of crystals considerably deviates from the sphere. What, in this case, does the wonderful program Nano Measurer define as the size?

In addition, it is not clear how homogeneous the grains are inside. To investigate the homogeneity, the XRD method might be applicable as the gold standard of materials science.

 

The paper may be published after the answer to the question about the size of the grains. A thorough check of the English grammar should be performed as well.

Author Response

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Reviewer 2 Report

The paper "Effect of Al content on the microstructural and grain growth kinetics of magnesium alloys" is well organized and provide sufficient experimental results to support the claim. The paper may be accepted after minor corrections listed below.

1. The line # 11-12 "The average grain size of each annealed specimen was measured quantitatively by isothermal annealing at 300-450 °C." should be rephrased. I think "by" is a misleading word here.

2. (ND ⊥ TD) should be elaborated in the text. Many readers might not be familiar to these notations.

3. For Fig. 1, I would recommend adding EDS data on clean area for all the samples. That will be more appealing to the readers.

Author Response

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Reviewer 3 Report

Dear Authors,

Congratulations on your work, which is focused on a very interesting subject. As any other paper in this phase, there are some amendments to do, whose can improve the overall quality of your paper. Thus, I'm providing below some comments and suggestions, trying to collaborate by this way in improving your paper:

 

1. The Abstract doesn't clearly state the literature gap found, as well as the main motivation to develop this work. Thus, please clearly state the gap found in the literature in the Abstract, Introduction and Conclusions. The main goals are also not clear in the Abstract.

2. The novelty brought by your work is also not properly pointed out. Thus, please state clearly the novelty that your paper represents for the scientific community, stating as well if your contribution is exclusively scientific or if there was some practical motivation behind the development of your work. Any industrial application based on this work should also be pointed out.

3. The Literature Review is well done, but readers prefer direct speech, describing briefly in what the work of previous Researchers has been focused on, methodology used and main results. Please avoid as much as possible generic ideas. Moreover, please avoid the use of large batches of references for a single idea.

4. The number of references is very scarce. Please try to deepen the study about previous works carried out in similar subjects.

5. Introduction is a little short. Please try to enlarge, increasing the number of references and ideas. Basically, try to enlarge the number of cases and results previously obtained by other Authors.

6. When describing the variables contained in each formula, please point out the units using the International Units System. 

7. In Experimental, please point out the microscopes (optical and electronic) used (brand and model), as well as the version of software used.

8. The Results are very interesting, but they should be discussed regarding other results previously obtained with similar materials or similar conditions. This is crucial and, without this, the paper cannot be considered for publication.

9. No contextualizaton of the Conclusions is presented.

10. The heating and cooling speeds during the treatments are not discussed in the conclusions.

11. The causes behind the effects observed are not properly discussed. Please deepen the discussion about the causes behind the effects observed.

Best wishes.

Kind regards.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

The article is to reveal the pinning effect of the secondary phase and the dragging effect of the solutes in MgAlZn alloys.

Unfortunately, the English of the article is rather poor, so that it was sometimes difficult to follow authors´ statements. In some sentences I found an improper use of the words, e.g.

Line 28       structure with limited number of slip systems

Line 43       uniform distribution of grain size maybe the authors meant normal size distribution

Line 70                 plates were prepared by…hot extrusion.          Maybe pressing?

Line 71                 what „XRF“ means?

Fig. 1 the EDS results for particles composition deviate significantly for A, B and C. No discussion of these results are given.

Figs. 2, 4 and 5. Authors claim to show either the normal or bimodal size distribution. Though the grains statistics (250 grains) is large enough, unfortunately sometimes it is difficult to see this in the figure. I suggest to increase the number of bins in the distribution.

Figure 14. It not clear from the text and from the caption, what the substructure distribution means. If this is the recrystallized and the deformed parts of the structure, how did the authors recognized them?

Figure 17. In the line profile shown in the figure, the authors gave the counts but not the concentration of the elements. Sometimes it can be misleading. Authors also wanted to study the Al solutes distribution near the grain boundary. EDX in SEM is totally not the technique which can provide any meaningful data. Depending on the solute concentration one need to use EDX in TEM or atom probe tomography approach.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Good job!