Effect of Aging Time on Microstructure and Properties of Cold-Rolled Ni-W-Co-Ta Medium–Heavy Alloy

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this paper, the authors experimentally examine several aging modes differing in the aging time of previously cold-rolled Ni-W-Co-Ta medium-heavy alloy. The cold rolling is used to reduce porosity of as-cast alloy and to increase the bonding forces between matrix and hardening phase. The aging is intended to reduce brittleness induced by severe deformation (90% reduction in thickness). The results are interesting and worth of publication, but the paper seems to be outside the scope of “Coatings”, because it does not deal with coatings and surface engineering. Therefore, it is recommended for resubmission into another MDPI journal, such as “Metals” or “Materials”. Besides, there are several comments to be addressed.

 

1. The aging is intended to decrease brittleness of cold-rolled samples, but the revealed decrease in elongation (Fig. 6) and the fracture patterns in Fig. 7 show that the material becomes even more brittle after this treatment. The authors should comment on this point and clearly state, did they reach their goals or not? Does the increase in strength compensate the decrease in elongation for the material application area?

 

2. Sometimes English is too rough with wrong usage of words, which obstructs understanding. Polishing of text is required. For instance, Section 2: “followed by subsequent air-cooling to achieve .” - to achieve what? “cutting from the deformation direction” - what does it mean?

 

3. Eq. (1) is not discussed and used. What is the meaning of this equation?

 

4. Fig. 2(a): it is strange that all peaks for precipitate phase coincide with the main phase. In the present figure, the peaks for precipitate phase are undistinguishable.

 

5. Present OMs in Fig. 3 are not informative without processing or highlighting specific features besides W particles. Scales of presented OMs are different for different aging times; this fact additionally obstructs comparison.

 

6. Ref. [15] does not provide the title of the journal.

Comments on the Quality of English Language

Sometimes English is too rough with wrong usage of words, which obstructs understanding.

Author Response

Dear editors and reviewers:

We sincerely thank you for your constructive comments and valuable suggestions on the manuscript, coatings-2853222. The suggestions mentioned by the reviewers are beneficial for us to improve the overall quality of our manuscript. In accordance with the reviewers’ comment and request, we have made modifications on the original manuscript, and carefully proof-read the manuscript to minimize typographical and grammatical errors. Furthermore, we have highlighted the changes from the original manuscript with red color in the revised manuscript. These changes will not influence the content and framework of the paper. We appreciate for Editors/Reviewers’ warm work earnestly, and hope that the correction will meet with approval. Please check the attachment for specific reply information. Thank you.

Our description on revision and answers to every question from the reviewers is summarized and enclosed. The revised manuscript, with modified sections red marked, is also attached for your approval.

Again, we earnestly appreciate the editors and reviewers’ warm work, and hope that the correction will meet with approval.

 

Thank you and all the reviewers for the kind advice!

 

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper presents intriguing points; however, there is room for improvement to align with the readership scope of the journal. To enhance clarity, please address the following issues:

1. Could the paper offer a more detailed analysis of microstructural changes during the aging process in the cold-rolled Ni-W-Co-Ta medium-heavy alloy, particularly focusing on Ni4W phase nucleation and growth mechanisms and their role in the observed increase in volume fraction over different aging times?

2. Regarding lattice distortion, reduced internal stresses, and decreased dislocation density discussed in the paper, can the authors elaborate on the mechanisms leading to these effects during the prolonged aging treatment of the cold-rolled Ni-W-Co-Ta medium-heavy alloy? How do these changes impact the alloy's overall mechanical properties?

3. The paper notes the attainment of maximum hardness, tensile strength, and yield strength after a specific aging treatment. Could the authors provide insights into the relationship between microstructural changes and mechanical properties, explaining how the alloy achieves peak hardness and strength at 766HV, 2286MPa (UTS), and 1989MPa (YS) following the 16-hour aging treatment at 700℃?

4. Concerning fracture morphology, the paper mentions a distinctive ductile-brittle mixed fracture characteristic. Could the authors delve further into the factors influencing this mixed fracture and provide microscopic insights into ductile and brittle regions in the cold-rolled Ni-W-Co-Ta medium-heavy alloy after aging treatment?

5. Given the alloy's relevance to warhead materials and demanding service environments, how do the observed microstructural changes and mechanical properties contribute to its suitability for harsh conditions? Additionally, could the paper briefly discuss potential applications or advantages in warhead material design resulting from the findings?

Author Response

Dear editors and reviewers:

We sincerely thank you for your constructive comments and valuable suggestions on the manuscript, coatings-2853222. The suggestions mentioned by the reviewers are beneficial for us to improve the overall quality of our manuscript. In accordance with the reviewers’ comment and request, we have made modifications on the original manuscript, and carefully proof-read the manuscript to minimize typographical and grammatical errors. Furthermore, we have highlighted the changes from the original manuscript with red color in the revised manuscript. These changes will not influence the content and framework of the paper. We appreciate for Editors/Reviewers’ warm work earnestly, and hope that the correction will meet with approval. Please check the attachment for specific reply information. Thank you.

Our description on revision and answers to every question from the reviewers is summarized and enclosed. The revised manuscript, with modified sections red marked, is also attached for your approval.

Again, we earnestly appreciate the editors and reviewers’ warm work, and hope that the correction will meet with approval.

 

Thank you and all the reviewers for the kind advice!

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

My comments are addressed sufficiently.

Reviewer 2 Report

Comments and Suggestions for Authors