Semi-Solid Slurries for Rheocasting of Hypoeutectic Al-Si-X Alloys Produced by Self-Stirring in Serpentine Channels
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn this work, two serpentine channels were designed and tested to produce semi-solid slurry with thixotropic behavior for rheocasting by self-stirring of A380 and A356 alloys, and the effects of the self-stirring in serpentine channels on microstructures of the Al alloys were investigated. The work of the paper is well-done, with some interesting results. However, it requires an appropriate revision before publication.
1. The Introduction section should point out the features and innovation of this study.
2. More details of the experiment should be provided, such as the method for quantitative analysis of the grains.
3. What is the cooling rates of aluminum alloy melt in different channels?
4. More theoretical analyses of the effects of the self-stirring in serpentine channels on microstructures of the Al alloys are welcome.
5. The English of the paper should be improved, especially in the use of the definite article.
Comments on the Quality of English LanguageIn this work, two serpentine channels were designed and tested to produce semi-solid slurry with thixotropic behavior for rheocasting by self-stirring of A380 and A356 alloys, and the effects of the self-stirring in serpentine channels on microstructures of the Al alloys were investigated. The work of the paper is well-done, with some interesting results. However, it requires an appropriate revision before publication.
1. The Introduction section should point out the features and innovation of this study.
2. More details of the experiment should be provided, such as the method for quantitative analysis of the grains.
3. What is the cooling rates of aluminum alloy melt in different channels?
4. More theoretical analyses of the effects of the self-stirring in serpentine channels on microstructures of the Al alloys are welcome.
5. The English of the paper should be improved, especially in the use of the definite article.
Author Response
Please see the attached word document
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe proposed manuscript is very interesting and novelty is provided. It deserves its final publication after a minor OBLIGATORY revision. For this purposes the followed suggestions are indicated:
1. The Abstract should be revised and only simple present tense should be used;
2. In the Experimental procedure, it is hardly suggested that triplicate or duplicate for all experimentations should be included/explained. This involves all dimensions and values of unit that should at least considered the equipment error.
3. When the “Scheil” equation is mentioned, it is suggested that two references be included, being a book and a recently published article into Metals /MDPI, as followed:
A.W. Kurz, D.J. Fisher, Fundamentals of Solidification, Trans. Tech. Public, Switzerland, 1992
B. Metals 2023, 13(10), 1710; https://doi.org/10.3390/met13101710
Comments on the Quality of English LanguageNo substantial comments, but Abstract should be revised in order to utilize only simple present tense.
Author Response
Please see the attached word document
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsGood Article,
Small comments
1. Compare the semi solid processing with HPDC and conventional die casting in introduction (merits/demerits) shortly.
2. Add schematics of the experimental set up.
3. Quality/resolution of figure 2 is very poor.
4. Why did not you compare results of the mechanical properties with conventional die casting process. Its easy, you have good work but nothing to compare with.
5. Always have a space between unit and number.
Make these changes and resubmit the article for publication
Author Response
Please see the attached word document
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsIn the paper entitled „Semi-solid slurries for rheocasting of hypoeutectic Al-Si-X alloys produced by self-stirring in serpentine channels” Authors present the results of studies concerning the influence of the runner construction on the microstructure of selected Al base alloys i.e. Al-Si-Cu and Al-Si-Mg cast in the semi-solid state. The problems presented in the paper are not completely novel, and the whole presentation is unclear. The presented results could be stated as preliminary studies in the rheocasting technology and should be widened for more detailed metallographic research and mainly the determination of the mechanical properties of castings. Therefore, in my opinion, the presented studies are not complete and discussion based on obtained results is so general that it degrades the scientific quality of the manuscript. Summing, in my opinion, the scientific value of this paper is not proper for METALS standards and I suggest reject it. However, if the Authors would like to send the improved manuscript once again to the Journal the detailed comments are given below:
#1: The aim of the studies is not clearly defined. It is not clear that the aim is the development of new technology or improvement of solutions that exist in the literature and foundry engineering practices. Therefore the manuscript does not indicate the novelty of the presented studies.
#2: On page 5 the Authors mentioned that: “The melts in weight of 420-460 g were produced into an electric furnace at 720-730°C, degassed with C2Cl6, refined with Al-5Ti-B, and modified with Al-10Sr to get 100 ppm Sr.”. However, both used master alloys i.e. A-5Ti-B and Al-10Sr are inoculants and their role is modification of Al base alloy microstructure, suitable alpha (Al) grains and eutectic Si. The above-mentioned statement does not clearly define the role of the master alloy Al-5Ti-B. Additionally in the paper is not defined the final amount of Ti and B. Moreover Authors completely omit the influence of the above-mentioned inoculants on the final microstructure. In my opinion is necessary to obtain a reference sample i.e. without inoculation to clearly evaluate the influence of the runner construction on the microstructure of studied alloys.
#3: The obtained results, widened by research of the mechanical properties of studied alloys need to be compared with results obtained by other researchers for similar alloys. On the base this analysis the Authors can evaluate the efficiency of proposed in the paper the runner construction.
#4: Presented in the paper microstructures are typical for cast Al-Si-Cu and Al-Si-Mg alloys and contain alpha (Al) and eutectic (Al + Si). Authors defined only general the presence of another phase i.e. Al2Cu, but did not indicate it precisely in the microstructure. Phases for example Mg2Si or others are not shown however undoubtedly exist what results from the chemical composition of studied alloys. I strongly suggest improving OM and SEM research and the discussion of these results. Mainly is necessary to show microstructure in OM at a small magnification as the Authors present in Fig. 1 and improve the SEM+EDS studies and conduct it also for Al-Si-Mg alloy.
Author Response
Please see the attached word document
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe author has carefully revised the paper in accordance with the revision suggestions, and the paper can be accepted in its present form.
Author Response
Response to Reviewer 1 Comments, (Round 2)
Dear reviewer, thank you very much again for taking your valuable time to review this manuscript and help us to get a better paper.
Kind Regards,
The authors.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsSecond Review of the paper metals-2917080
I read the revised version of the paper very carefully and I changed my decision to "Minor Revision". The Authors strongly improved the paper and I accepted all answers to my previous comments. In the actual version of the paper, I have only one suggestion:
#1: The scheme presented in the graphical abstract concerning the CAD 3D model of the runner contains specific angles with schematic changes in grain shape in the structure of the alloy is very cognitive. I think this is a concept of Authors studies and the main assumption of runner construction to obtain the rheocasting effect. Therefore I suggest adding this figure to the paper of course with suitable comment in the main text.
Author Response
Response to Reviewer 4 Comments, (Round 2)
Dear reviewer, thank you very much again for taking your valuable time to review this manuscript and help us to get a better paper.
In attention to your assertive suggestion, the 3D model of the runner has been included in the figure 3. The comments about the concept of the morphological evolution of the solid phase are written in the experimental method and in the conclusions.
Kind Regards,
The authors.
