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  • Yaqi Wu1,
  • Peter K. Liaw2 and
  • Yong Zhang1,*

Reviewer 1: Anonymous Reviewer 2: Anonymous

Round 1

Reviewer 1 Report

The work presents new experimental results on a hot topic of recent years - HEA. For this reason, it is highly likely that it may be interesting and useful to someone. However, the paper itself needs some additional work. The main complaint is about the introduction. It looks like an brief version of some kind of overview on HEA in general. But it is weakly connected with the alloys discussed in the paper, the methods of their manufacture and other main contents of this work. In particular, it is not clear what Table 1 (and its associated text) or lines 89-98 are given for.

Second, there is a feeling that the presented results are few. More precisely, the spirit of science is lacking. After all, science is about the study of laws. And here any investigated patterns are not presented. For example, onу could expect the dependencies of the porosity of the obtained materials on time or sintering pressure.

Thirdly, I don't want to offend, but after reading section 4 “Discussion” there is feeling that it is kind of useless. It is not clear what new information the reader could take from there for himself...

Several more questions and notes:

  1. Abbreviation HEA can be used more often, since it was introduced.
  2. SPS abbreviation is not deciphered.
  3. Paragraph 2. It is not prescribed, what was sintered. Elemental powders? What are their characteristics?
  4. Line 180. What samples do these values correspond to?
  5. Table 3. How density of real NbTiAlTaV sample (7.44) can be greater than theoretical one (7.19 or 7.21)? There is probably some mistake…
  6. Line 192. Young's modulus? MPa?
  7. Line 203. According to Figure 4?
  8. Line 206. Low what?
  9. Lines 208 – 213. This text is difficult to understand. Please, reread it carefully.
  10. Line 229. “The surface energy causes a rapid increase in the relative density”. Incorrect sentence. A force can cause something, not energy.
  11. Line 237. Wire? What wire? Some wire is mentioned here the first time.
  12. Line 248. “by the above Al:Ti atomic ratio of close to 1:4” Where is it shown above?
  13. Line 249 “Al3Ti is the stable phase with the lowest interfacial energy in the AlTi compound”. It depends on alloy composition (See Al-Ti phase diagram).
  14. Line 250. “However, the experimental results show the presence of the ALTi2 phase, indicating that the sintering process has been completed, and the number of Al diffusions in Ti is low”. Number of diffusions?? Very strange term.
  15. Fig 6c. What the model is used here for?
  16. Line 256. Melting point of these elements have long been well known without any SEM and EDS.
  17. Line 260. diffusion of particles?..
  18. Line 267 “alloys have a certain degree of strength” – Useless sentence.
  19. Please, check English style of the entire text carefully one more time.

Author Response

Thank you for your comments. After reading the review comments, I discovered that there are several flaws in my paper, as well as other details, and I apologize for any difficulty this has caused you. I'd want to respond to your remarks as follows:

1、The incoherence in the opening has been corrected, and other changes have been made in the discussion.

2、Abbreviations and first proper nouns have also been corrected.

3、The particle size of the powder is 10 microns, and the purity is 99.9%. After the elemental powder is mixed evenly, the alloy with equal atomic ratio is prepared.  Some SEM images of powder were also added .

4、The theoretical density of NbTiAlTaV alloy was incorrectly written and has been corrected

5、The young's modulus of the alloy is measured in GPa。

6、In this paper, the alloy is cut into test samples by wire cutting technology。

7、Other details have been revised in the paper。

Thank you very much again.

Reviewer 2 Report

Interesting paper. Major revisions are in order for the authors to address the comments detailed below:

“Furthermore, the related high entropy alloy preparation technology has been continually improved in response to the alloy-preparation requirements, yielding some excellent research findings.”: see recent papers on HEA processing such as 10.1016/j.scriptamat.2021.114219, 10.1016/j.matdes.2020.108505 and 10.1007/s11661-019-05564-8 and revise the introduction to support this claim.

“entropy alloys), irradiation-resistant high-entropy alloys, corrosion-resistant high-entropy alloys”: this sentence seems incomplete. Double check.

“tropy alloys using powder metallurgy and laser cladding.”: references needed.

“SPS (Please spell it out the first time)”: clearly this was not reviewed prior to submission…

“ing temperature, short sintering time, and rapid cooling rate”: can this be quantified?

“The alloy has excellent comprehensive mechanical properties with”: what justified the improvement in mechanical properties?

“The multicomponent TiZrNbMoV and NbTiAlTaV”: is this equiatomic? What is the chemical composition?

“from a typical bcc (Please spell it out the first time)”: same as above…

Do the authors have pure Ti, Nb and Ta?? And their diffraction peaks fall in the exact same position? This is weird. Also, several peaks have 2 phases assigned. This is not possible. How was peak identification performed? Clarify.

“Due to the small amount of metal compounds in the alloy”: how small? Can this be quantified?

Table 2: can you measured in the SEM/EDS compositions below 1 at%? This is below the resolution of most SEM equipments…

Is the compression curve correct? Why isn’t there a linear behavior at the beginning?

“g sintering is significantly lower when compared to as-cast alloys”: why? Discuss.

Author Response

Dear Editor：

Thank you for your insightful and careful remarks in this review, which have greatly aided in the improvement of the paper.At the same time, I am aware of my numerous flaws.Respond to your remarks as follows:

1、Your suggested references have been added.

2、Some of the language is not fluent, and some nonsensical sentences have been changed.

3、Proper noun abbreviations are completed on their first usage.

4、Alloys are equiatomic.

5、The diffraction peaks of Ti、Zr、Nb are not all in the same place. Because there is no peak separation in image processing, the locations in labeling are quite near, producing some confusion. In order to improve, a peak splitting technique for general diffraction will be performed.

6、SEM and EDX data are original.

7、The compression curve is right as well. Because the alloy has pores, the early stage is not linear, and the initial compression strength is relatively low.

There are still some missing details, which have been steadily added to the article. Thank you once more for your suggestions and revisions.

Round 2

Reviewer 1 Report

Unfortunately, the changes made by the authors do not eliminate the noted flaws. The Introduction is so far weakly connected with the alloys discussed in the paper, the methods of their manufacture and other main contents of this work. And the Discussion is poor with useful information.

I am repeating unanswered or uncorrected questions and notes:

  1. Abbreviation HEA can be used more often, since it was introduced.
  2. Line 182. What samples do these values correspond to?
  3. Table 3. How density of real NbTiAlTaV sample (7.44) can be greater than theoretical one (7.19 or 7.21)? There is probably some mistake…
  4. Line 194. “The elastic modulus of these two alloys” “Elastic” is absent.
  5. Line 208. Low what?
  6. Lines 210 – 215. This text is difficult to understand. Please, reread it carefully.
  7. Fig 6c. What the model is used here for?

 

And some more:

  1. Line 48. “…powder-metallurgy HEAs, HEAs, and so on”. Excess “HEAs”.
  2. Line 239. “is dissolved precipitation” What kind of precipitations? The starting material was pure powders.
  3. Line 261 and 265-266. I can’t see the comparison of mechanical properties of sintered HEAs (from this work) with the as-cast alloys.
  4. Line 268-269 “However, we discovered that the elastic modulus of the two alloys is similar to that of human bone” Does it have some significance?

Author Response

Dear editor

Thanks for your patience. As for suggestions, my reply is as follow:

  1. Yes. This is a problem worthy of attention, and duplicate parts have been modified to abbreviate.
  2. The test density of TiZrNbMoV is 7.192g/cm3, and the test density of NbTiAlTaV is 7.72178g/cm3.
  3. There is indeed an error in the description of the data.Correct data as shown in the second reply.
  4. The "elastic" were complete.
  5. Low temperature,I mean, the temperature is not there.
  6. This paragraph is intended to describe the change of the compression stress-strain curve. Before changing the picture, the initial part of the compression curve was not linear. Because another reviewer questioned, the image was altered. However, following the replacement, the descriptive statement does not follow the trend of the curve, resulting in a mismatch between the text and text.We chose to utilize the original image and seek truth from facts after consulting with our tutor.
  7. Figure 6c was made using the computer's 3D sketching program. Because the substance was not taken or recorded immediately after being produced, an image like this was made in this paper represent the appearance of the actual sample. Figure d depicts the real material, although it must be tested, thus some processing traces are visible.
  8. Have been modified.
  9. The dissolution and precipitation mass transfer process occurs during the sintering process, which includes both liquid and solid phases. The solid phase is distributed in the liquid phase, and tiny particles will first dissolve in the liquid phase and then spread throughout the liquid phase, increasing the concentration of this location in the liquid phase.When saturation is attained, precipitation will form on the liquid phase's surface, causing the grain boundary to shift and the pores between big and tiny particles to fill, resulting in sintering densification.
  10. I'm sorry. This issue has gone unnoticed. In reality, there is a data comparison. This document includes a text description as well as an article citation. For reference, images of the comparative data will be supplied in the supplemental file. 
  11. The matierial of TiZrNb system, which has good biological compatibility in biological applications and can achieve a certain strength and shape, is promising in biomedical, so our experiment in the preparation of materials containing space, modulus, and bone in some parts of the modulus of close may develop artificial joint materials. Furthermore, the existence of pores can enhance the absorption and precipitation of bone components, as well as the development of regeneration bone, therefore we believe it is significant.

The above is the content of my reply to several recommendations.Thank you once again for the editor's assistance.

Reviewer 2 Report

The paper was significantly improved and acceptance is recommended.

Author Response

Thank you!

Round 3

Reviewer 1 Report

It was pointed out two times on the flaw about the Introduction. It looks like a brief version of some kind of overview on HEA in general and is almost not connected with the alloys discussed in the paper, the methods of their manufacture and other main contents of this work. From almost 120 lines of it just 5 lines (87-91) concern powder HEAs. Sintering is mentioned in the next paragraph, but is about SPS which, as I see, was not used by you in this work. Lines 106-117 and table 1 are obviously surplus. Etc. Please, finally, make some answers or correct the paper.

It would also be pretty if you rewrite the Discussion as there is almost no some useful information.

  1. You answer: “The test density of TiZrNbMoV is 7.192g/cm3, and the test density of NbTiAlTaV is 7.72178g/cm3.” It should be pointed in the paper.
  2. You answer: “Figure 6c was made using the computer's 3D sketching program….”. It is mentioned nowhere in the paper. So one will have reasonable question reading the paper: “What is it necessary for?”
  3. It is unclear so far. What kind of precipitations are you talking about? Precipitations of what? The starting material are pure powders. You are heating them. When some precipitates can form?
    And by the way, may be: “is dissolved precipitation.” → “is dissolving of precipitations.”
  4. You answer: “The matierial of TiZrNb system, which has good biological compatibility”. I agree with what you talk about pores. But it is written about elastic modulus in the paper. Does it really matter that it would be similar to that of human bone?

Author Response

Dera editor，

Thank you for your serious and responsible attitude. In these rounds of reviews, I really saw my own shortcomings and problems in details. I was lucky enough to meet you in order to make the article more qualified.Some of your suggestions have been revised in the article, but some of them need to be further explained to you. The answers are as follows：

1、The introduction failed to get to the topic of the article quickly, which is too lengthy, but it has been revised after discussion with the professor. At first, we want to express the work in the summary group in Table 1, because the work in this paper is also based on the work in the group, but it may be inappropriate to put it in the introduction. So I removed it and rewrote the introduction. I hope it is qualified this time.

2、With regard to density, these two values are theoretical density, and the table is the actual density measured using Archimedes method. The theoretical density is to calculate the volume of each constituent element in the alloy according to the percentage content, and then calculate the theoretical density. The cube of 10*10*10mm is used to calculate the theoretical density of the sample. This revision also checks our original data. There was a problem with the previous data calculation, but now it has been modified.

3、The problem of figure c, according to the suggestions, adds a little explanation and description in the article to avoid readers' misunderstanding of this part.

4、The description of the discussion part is not clear.Precipitation and dissolution is a mass transfer process only in the sintering type which contains both liquid phase and solid phase. This part of the description is to explain what types of mass transfer there are in sintering, but it is obviously superfluous, so the discussion has also been deleted and modified.

5、In the design and development of biomedical materials, biocompatibility is the most important, but the mechanical properties are also necessary, close to the bone modulus can be a better substitute, and the hardness can not be too high to avoid stress shielding caused by human damage.

The above is to answer some confused and ambiguous questions. Thank you again.

Author Response File: Author Response.docx