Effect of Cooling Method on Microstructure and Microhardness of CuCrFeMnNi High-Entropy Alloy
, Ruifeng Zhao 2,*, Hechuan Geng 1, Bo Ren 1,3,*, Zhongxia Liu 1, Jianxiu Liu 1, Aiyun Jiang 1 and Baofeng Zhang 1Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors.
The paper titled “Effect of cooling method on microstructure and microhardness of CuCrFeMnNi high-entropy alloy" presents original and interesting results. However, the paper needs to be revised to improve the quality of presentation and understanding based on the following comments:
1. Please follow the author guidelines how to cite the references. It should not be written with superscripted citation. It should be written as [1] etc. Please check other citations in this paper. [Line 28-33]
2. Please add one or two more references to support these statements [Line 77-82]
3. It should be written as "The alloy was subjected to isothermal aging,...". Since, it has been done. [Line 86]. Please revise other writings that has the same condition.
4. Please write in details the methods of cooling such as how long the immersion and calculated cooling rate was done for each coiling method. [Line 97-99]
5. Please explain more about nature or composition of FCC1, FCC2 and about rho phase Cr5Fe6Mn8. Explain also how to determine or analyze that there is rho phase Cr5Fe6Mn8, not other phase composition. [Line 113-115].
6. Please cite at least two references about Equation of Formula (1) [Line 116-117].
7. Please add references that support this statement [Line 134-135].
8. Please add references that support this statement [Line 137-138].
9. This statement is not the same with the data in Table 1. Namely, using AC, the relative content of rho phase is lower than FC. It should be increased based on the authors’ statement. The relative content of rho phase increase in WC compared to OC and AC cooling method. Please discuss it more in this part. [Line 141-142]
10. Please explain what happened in the condition that there are XRD main peaks shift to smaller angles of diffraction, due to different cooling rate. [line 143-145]
11. Figure 2 to 6 should also show and discussed where FCC1 and FCC2 phase located to show that FCC2 as the primary phase and FCC1 as ithe secondary phase in the alloy. [Line 148]
12. Please use contrast color to show ID and DR in the Figure 2 to be seen easier. [Line 155]
13. Please write magnification during SEM-EDS analysis in Figure 3-6. The explanations of figure 3 to 6 are still not clear. Each title of figure should has caption of each photo with explanation. Even though, Table 2 help reader to understand the data. [Line 159-170]
14. Please explain how to determine the composition of black particles in Figure 3-6[Line 167]
15. There is incomplete sentence in Line 183 that should be completed.
16. If it is possible, it is better to add one more references that support this statement. [Line 193-194]
17. Is there any data that show that cooling rates of OC and AC are similar? It should be different. [197-198]
18. Please explain in the discussion based on data that FC alloys contains FCC2 as its primary phase. Is it based on FC sample? [Line 208]
19. Please revise the paper based on the above comments and in the paper. Please highlight the revised part with green color or other and to be reviewed again.
Kind regards,
Comments for author File: 
Comments.pdf
Author Response
Coatings
Editorial Office
Dear editors,
Thanks for your great efforts and reviewers’ thoughtful comments, all of which have been incorporated into the revised manuscript. Detailed descriptions are listed as follows and marked by red color in the revised manuscript (with marked).
Reviewer 1
Comment 1: Please follow the author guidelines how to cite the references. It should not be written with superscripted citation. It should be written as [1] etc. Please check other citations in this paper. [Line 28-33]
Response 1: According to Comment 1, the citation format of the references in the article has been modified.
Comment 2: Please add one or two more references to support these statements [Line 77-82]
Response 2: According to comment 2, two relevant references were added in the revised manuscript to support the effect of cooling methods on the microstructure and properties of high entropy alloys. The relevant literature is as follows.
- Xiong, K.; Huang, L.; Wang, X.; Yu, L.; Feng, W. Cooling-rate effect on microstructure and mechanical properties of Al5CoCrFeNi high-entropy alloy. Metals.2022, 12(8): 1254. https://doi.org/10.3390/met12081254
- Yu,H.Y.; Fang, W.; Chang, R.B.; Bai, X.; Zhang, X.; Liu, B.X.; Jiang,F.; Yin, F.X. Effects of annealing temperature and cooling medium on the microstructure and mechanical properties of a novel dual phase high entropy alloy, Mater. Charact. 2020, 163: 110291, https://doi.org/10.1016/j.matchar.2020.110291
Comment 3: It should be written as "The alloy was subjected to isothermal aging,...". Since, it has been done. [Line 86]. Please revise other writings that has the same condition.
Response 3: According to comment 3, the incorrect grammar in the text has been corrected.
Comment 4: Please write in details the methods of cooling such as how long the immersion and calculated cooling rate was done for each cooling method. [Line 97-99]
Response 4: According to comment 4, a detailed cooling method has been added to the revised version. Reference [23] provides the approximate cooling rates corresponding to each cooling mode.
Comment 5: Please explain more about nature or composition of FCC1, FCC2 and about rho phase Cr5Fe6Mn8. Explain also how to determine or analyze that there is rho phase Cr5Fe6Mn8, not other phase composition. [Line 113-115].
Response 5: Previously, Chen et al. [3] studied the age hardening phenomenon of AlxCrFe1.5MnNi0.5 HEAs, and found that the BCC phase partially transformed into r phase (Cr5Fe6Mn8) led to the increase of hardness. The CuCr2Fe2MnNi HEA was prepared using an arc melting process. The effects of heat treatment temperature and time on its microstructure and hardness were investigated. The phase structure was found to consist of two FCC phases (FCC1 and FCC2) plus a minor amount of Cr5Fe6Mn8 phase [4]. We have also prepared CuCrFeMnNi HEA powders and bulk materials using mechanical alloying and powder metallurgy techniques. The CuCrFeMnNi powder consists of a FCC primary phase and a BCC secondary phase. After vacuum annealing between 700-900°C, the phase structure transforms into two FCC phases (FCC1 and FCC2), a minor BCC phase, and a minor Cr5Fe6Mn8 phase [5]. Due to the sintering and aging effects, the phase of CuCrFeMnNi after sintering consists of two FCC phases (FCC1 and FCC2) plus a minor amount of Cr5Fe6Mn8 phase [6]. The Cr5Fe6Mn8 phase is an intermetallic compound with a tetragonal structure. Its primary constituents are Cr, Fe, and Mn, and it exhibits high microhardness (1273 HV). In XRD, it is primarily observed in the range of 2θ=41° to 49° [3]. Therefore, the increase in hardness of the aforementioned three alloys is attributed to the strengthening through precipitation of the Cr5Fe6Mn8 phase. The FCC1 and FCC2 phases share the same crystal structure, differing only in the main elements of their solid solutions. The FCC1 phase primarily consists of Fe-Cr-Mn, whereas the FCC2 phase is primarily composed of Cu-Ni-Mn. The differing lattice constants of the two phases result in a double-peak phenomenon in the XRD patterns. In this study, the CuCrFeMnNi sintered alloy underwent isothermal aging and four different cooling methods. The phases comprised two types of FCC phases (FCC1 and FCC2) plus a minor amount of the Cr5Fe6Mn8 phase, closely resembling previous research findings.
- Chen, S.T.; Tang, W.Y. ; Kuo, Y.F.; Chen, S.Y.; Tsau, C.H.; Shun, T.T.; Yeh, J.W. Microstructure and properties of age-hardenable AlxCrFe5MnNi0.5alloys, Mater. Sci. Eng. A. 2010, 527: 5818-5825. https://doi.org/10.1016/j.msea.2010.05.052
- Ren, B.;Liu, X.; Cai, B.; Wang, M.X.; Shi, L. Aging behavior of a CuCr2Fe2NiMn high-entropy alloy, Mater. Design. 2012, 33: 121-126. https://doi.org/10.1016/j.matdes.2011.07.005
- Zhao, R.F., Ren, B.; Zhang, G.P.; Liu, Z.X.; Zhang, J.J. Phase transition of as-milled and annealed CrCuFeMnNi high-entropy alloy powder, Nano, 2018, 13(9): 1850100. https://org/10.1142/S179329201850100X
- Ren, B.; Zhao, R.F. Elemental synergistic effect in CoxCrCuFeMnNi high-entropy alloys and its influence on phase and magnetic properties, J. Mater.Res. Technol. 2023, 23: 2542-2556. https://doi.org/10.1016/j.jmrt.2023.01.171
Comment 6: Please cite at least two references about Equation of Formula (1) [Line 116-117].
Response 6: We have defined the relative content formulas for each phase in our previous research (References [18] and [19]). According to Comment 6, these two references were cited in the revised manuscript.
Comment 7: Please add references that support this statement [Line 134-135].
Response 7: Reference [18] studied the annealing phase transformation behavior of CrCuFeMnNi high entropy alloy powder and found that the relative contents of FCC1, FCC2, and r phases were different at different annealing temperatures, indicating that these phases exhibited dynamic precipitation or decomposition phenomena. This study also presents a similar phenomenon. According to Comment 7, corresponding references have been added to the revised manuscript.
Comment 8: Please add references that support this statement [Line 137-138].
Response 8: According to Comment 8, relevant reference has been added to the revised manuscript.
Comment 9: This statement is not the same with the data in Table 1. Namely, using AC, the relative content of rho phase is lower than FC. It should be increased based on the authors’ statement. The relative content of rho phase increase in WC compared to OC and AC cooling method. Please discuss it more in this part. [Line 141-142]
Response 9: We are grateful to the reviewer for keenly identifying the contradictory statements in the article. Table 1 shows that the r phase content in the FC state alloy is higher than that in the alloys produced by the other three cooling methods. The article states that high melting point phases precipitate preferentially, with a relatively high content, and undergo dynamic transformation during the heat treatment process. We believe that the FC state alloys cool at a slower rate, causing the Cr-Fe-rich FCC1 phase to preferentially decompose into the r phase, leading to a lower FCC1 phase content and a higher r phase content. In the AC, OC, and WC states, the cooling rate is relatively rapid, inhibiting the decomposition of the FCC1 phase, and resulting in a lower r phase content compared to the FC state alloy. However, among these three cooling states, the WC state exhibits the fastest cooling rate and the highest content of r phase. In the revised manuscript, we have added relevant expressions to make them no longer contradictory.
Comment 10: Please explain what happened in the condition that there are XRD main peaks shift to smaller angles of diffraction, due to different cooling rate. [line 143-145]
Response 10: At low cooling rates (FC state), each element diffuses sufficiently to form FCC1, FCC2, and r phases. The main solid solution element of FCC1 phase is Cr-Fe, the main solid solution element of FCC2 phase is Cu-Ni, and the main component of r phase is Cr-Fe-Mn. At high cooling rates (AC, OC, and WC states), both the FCC2 phase and r phase content decrease, indicating that alloying elements in the FCC2 phase and r phase diffuse with each other, leading to an increase in the FCC1 phase content. Among these alloying elements, the atomic radius in descending order is Mn>Cu>Cr>Ni>Fe. The Mn element caused by the decomposition of r phase diffuses into FCC1 and FCC2, resulting in an increase in their lattice constants. Therefore, the main peaks of FCC1 and FCC2 phases in XRD shift towards a small angle direction. The relevant statements have been added to the revised manuscript.
Comment 11: Figure 2 to 6 should also show and discussed where FCC1 and FCC2 phase located to show that FCC2 as the primary phase and FCC1 as the secondary phase in the alloy. [Line 148]
Response 11: According to comment 11, FCC1 and FCC2 phases have been added in Figures 2 to 6. Figures 2a and 3 show the FC state alloy, with FCC2 being the primary phase and FCC1 being the secondary phase in the alloy. Other figures show the AC, OC, and WC state alloys, with FCC1 being the primary phase and FCC2 being the secondary phase in the alloy. The main component of phase r is Cr-Fe-Mn, which is similar in composition to the FCC1 phase and mainly dispersed in the FCC1 phase.
Comment 12: Please use contrast color to show ID and DR in the Figure 2 to be seen easier. [Line 155]
Response 12: According to comment 12, contrasting colors were used in Figure 2 to highlight the ID and DR areas.
Comment 13: Please write magnification during SEM-EDS analysis in Figure 3-6. The explanations of figure 3 to 6 are still not clear. Each title of figure should has caption of each photo with explanation. Even though, Table 2 help reader to understand the data. [Line 159-170]
Response 13: According to Comment 13, the magnification and scale are added in Figure 3-6, and the DR and ID areas are marked, and the picture description is added to each picture. The SEM results were modified in this revised manuscript. [ Line 216-236 ]
Comment 14: Please explain how to determine the composition of black particles in Figure 3-6[Line 167]
Response 14: The composition of black particles ( C region ) in Figure 3-6 was measured by point scanning. Three points were measured in each image, and the average content of each element was listed in Table 2.
Comment 15: There is incomplete sentence in Line 183 that should be completed.
Response 15: This incomplete sentence is superfluous and has been deleted in the revised version.
Comment 16: If it is possible, it is better to add one more references that support this statement. [Line 193-194]
Response 16: Our previous research results show that the main component of FCC1 phase is Cr-Fe-Ni-Mn, and the main component of FCC2 phase is Cu-Ni-Mn. When the content of FCC1 phase increases and the content of FCC2 phase decreases, the hardness of the alloy increases, indicating that the hardness of the former is higher than that of the latter. We refer to other high-entropy alloy systems, such as CoCrFeNiCu alloy system[7,8], which is also composed of two FCC phases, but it has not been reported that the hardness of FCC1 phase is higher than that of FCC2 phase. Therefore, we cannot supplement other relevant literature in this paper.
- Li, N.; Jia, C.L.; Wang, Z.W.; et al. Achieving a high-strength COCrFeNiCu high-entropy alloy with an ultrafine-grained structure via friction stir processing, Acta Metallurgica Sinica, 2020, 33: 947-956.
- Hsu,Y.J.; Chiang, W.C.; Wu, J.K. Corrosion behavior of FeCoNiCrCux high-entropy alloys in 3.5% sodium chloride solution, Materials Chemistry and Physics, 2005, 92(1): 112-117, https://doi.org/10.1016/j.matchemphys.2005.01.001.
Comment 17: Is there any data that show that cooling rates of OC and AC are similar? It should be different. [197-198]
Response 17: Compared with AC state alloy, OC state alloy has a higher cooling rate, and it is unreasonable to state in the article that the cooling rates of the two are similar. The relevant expressions have been deleted and revised in the revised manuscript.
Comment 18: Please explain in the discussion based on data that FC alloys contains FCC2 as its primary phase. Is it based on FC sample? [Line 208]
Response 18: We estimated the relative content of each phase based on XRD results, as shown in Table 2. It can be seen that the relative content of FCC2 phase is about 52.2%, FCC1 phase is 27.4%, and r phase is 20.4%. Therefore, in FC state alloys, FCC2 phase is the primary phase and FCC1 phase is the secondary phase.
Comment 19: Please revise the paper based on the above comments and in the paper. Please highlight the revised part with green color or other and to be reviewed again.
Response 19: Based on your comments, we have carefully revised and supplemented the content of the paper, highlighted in red.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors1) What is the cooling rate in each different cooling method?
2) Why did you select to conduct heat treatment at 800 C for 12h?
3) Since the HEA was fabricated by powder metallurgy, subsequent heat treatment may affect not only the phase constitution but the sintering outcome as well.
4) Materials and methods section is poor. You don`t provide any information about the fabrication method and/or the heat treatment.
5) Figure 2 has poor quality. It needs improvement.
6) Why didn`t you conduct ageing after the solution heat treatment? Especially for the oil and water cooled samples, after ageing, precipitation hardening could occur.
7) The only material test you conducted is microhardness. More testing including mechanical testing, wear and corrosion testing would help to understand how the changes induced in the microstructure with HT affect the alloy properties.
8) Furnace cooled HEA has the largest volume fraction of the hard ρ phase, nonetheless, it appears to have the lowest microhardness. Please explain this discepancy.
9) High magnification SEM images are needed to study the development of fine precipitates.
The final comment for this manuscript is that it is an interesting topic but this works contains very few results. More testing and more analysis is needed in order to publish this paper.
Taking all the above into consideration, this work cannot be accepted
Author Response
Coatings
Editorial Office
Dear editors,
Thanks for your great efforts and reviewers’ thoughtful comments, all of which have been incorporated into the revised manuscript. Detailed descriptions are listed as follows and marked by red color in the revised manuscript (with marked).
Reviewer 2
Comment 1: What is the cooling rate in each different cooling method?
Response 1: The cooling rate of alloys varies at different cooling temperature stages under different cooling methods. The cooling rates of four cooling methods were calculated from the temperature difference and time difference between furnace temperature and room temperature, and the cooling rates given in reference [23] were also referenced. The approximate cooling rates corresponding to the four cooling methods are: 0.02~0.03 oC/s (FC), 0.9~1.8 oC/s (AC), > 20 oC/s (OC), > 75 oC/s (WC).
Comment 2: Why did you select to conduct heat treatment at 800 oC for 12h?
Response 2:We have studied the aging behavior of as cast CuCr2Fe2MnNi high entropy alloy and found that the alloy has the highest microhardness at 800 oC for 12 h, exhibiting the best aging hardening phenomenon [4]. Based on this, the temperature and time for heat treatment were selected as 800 oC and 12 h, respectively.
- Ren, B.;Liu, X.; Cai, B.; Wang, M.X.; Shi, L. Aging behavior of a CuCr2Fe2NiMn high-entropy alloy, Mater. Design. 2012, 33: 121-126. https://doi.org/10.1016/j.matdes.2011.07.005
Comment 3: Since the HEA was fabricated by powder metallurgy, subsequent heat treatment may affect not only the phase constitution but the sintering outcome as well.
Response 3: The CuCrFeMnNi high-entropy alloy studied in this paper is prepared by hot pressing sintering process, and then subjected to heat treatment at 800 oC and 12 h, and then cooled in four ways. The high-entropy alloy after heat treatment must be different from the sintered alloy. By analyzing the changes of its microstructure and properties, it provides a reference for the future heat treatment process to improve the microstructure and properties of high-entropy alloys, which is the main purpose of this paper.
Comment 4: Materials and methods section is poor. You don`t provide any information about the fabrication method and/or the heat treatment.
Response 4: According to Comment 4 [7], the materials and methods for preparing high-entropy alloys are supplemented in the revised manuscript, and the method of heat treatment is added.
Comment 5: Figure 2 has poor quality. It needs improvement.
Response 5: According to Comment 5，Fig.2 has been modified to show the ID and DR areas by contrast color.
Comment 6: Why didn`t you conduct ageing after the solution heat treatment? Especially for the oil and water cooled samples, after ageing, precipitation hardening could occur.
Response 6: Thanks to the reviewer 's suggestion, in the follow-up research work, we will further study the effect of solid solution + aging on the microstructure and properties of high entropy alloys. The purpose of this paper is to study the effect of heat treatment cooling method on the microstructure and microhardness of high entropy alloy.
Comment 7: The only material test you conducted is microhardness. More testing including mechanical testing, wear and corrosion testing would help to understand how the changes induced in the microstructure with HT affect the alloy properties.
Response 7: Limited to the experimental conditions, we only considered the influence of heat treatment cooling method on microhardness in terms of mechanical properties. Thank you for your suggestions. When the follow-up conditions are available, we will carry out other tests and analysis on mechanical properties, wear and corrosion.
Comment 8: Furnace cooled HEA has the largest volume fraction of the hard ρ phase, nonetheless, it appears to have the lowest microhardness. Please explain this discepancy.
Response 8: Previous studies [] have shown that the microhardness of the ρ phase in the sintered CuCrFeMnNi high-entropy alloy is the highest, followed by the FCC1 phase, and the FCC2 phase has the lowest hardness. The content of the three phases has an important influence on the microhardness of the alloy. In FC state, the relative content of ρ phase in CuCrFeMnNi high entropy alloy is higher, 5.6 % higher than that in AC state, but the relative content of FCC1 phase is 20.2 % lower than that in AC state, which leads to the hardness of FC state alloy is lower than that of AC state alloy. With the increase of cooling rate, the content of FCC1 phase and ρ phase increased, resulting in the increase of hardness.
- Zhao, R.F., Liang, Y.C., Ren,B., Jiang, A.Y., Liu, J.X., Zhang, B. Effect of elemental synergism on the mechanical behavior of CoCrCuFeMnNi high-entropy alloy system. Met. Mater. Int. 2023, https://doi.org/10.1007/s12540-023-01586-5
Comment 9: High magnification SEM images are needed to study the development of fine precipitates.
Response 9: Thank you for your comments. Limited to the experimental conditions, our SEM equipment can observe the microstructure of the alloy at 5000 magnification, and the photos of the alloy at higher magnification are blurred and the precipitated phase cannot be observed.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsIn this article, CuCrFeMnNi high entropy alloy was heat-treated at 800 °C for 12 h and the microstructure and microhardness of the alloy were analyzed by XRD, SEM, EDS, and microhardness tester. The topic is original and relevant in research the field. The conclusions are consistent with the evidence and arguments presented in this article.
Comments :
1. L96-99 : Indicate the value of the cooling rate under each conditions (FC, AC, OC, WC).
2. L183 : Delete it.
3. L185-190 : Explain a reason that the hardness of this study is considerably smaller than 534 HV in Ref25. In addition, what should you do to be able to get closer to this value?
4. In conclusion section, describe what does it add to the subject area compared with other former published materials.
Comments on the Quality of English Language
As there is a colloquial expression in some phrase, repair it in written language expression. An example: but... ---> however...
Author Response
Coatings
Editorial Office
Dear editors,
Thanks for your great efforts and reviewers’ thoughtful comments, all of which have been incorporated into the revised manuscript. Detailed descriptions are listed as follows and marked by red color in the revised manuscript (with marked).
Reviewer 3
Comment 1: L96-99 : Indicate the value of the cooling rate under each conditions (FC, AC, OC, WC).
Response 1: According to Comment 1, we estimated the cooling rate of the alloy under four cooling methods, and referred to the data of Reference [ 23 ]. The cooling rates of the alloy under the four cooling methods are roughly: 0.02~0.03 oC/s (FC), 0.9~1.8 oC/s (AC), > 20 oC/s (OC), and > 75 oC/s (WC).
Comment 2: L183 : Delete it.
Response 2: Thank you for the reviewer 's reminder that the redundant content has been deleted in the revised manuscript.
Comment 3: L185-190 : Explain a reason that the hardness of this study is considerably smaller than 534 HV in Ref25. In addition, what should you do to be able to get closer to this value?
Response 3: Thanks to the reviewer 's keen discovery. During the experiment, we also found this problem and analyzed it. The phase structure of CuCrFeMnNi alloy in the sintered state is FCC1, FCC2 and r phase, and the relative contents of the three phases are 40.2 %, 31.8 % and 28 %, respectively [7]. The microhardness of the rphase is the highest, which contributes the most to the hardness improvement of the alloy, followed by the FCC1 phase. In this study, the highest microhardness is WC state alloy, the content of FCC1 phase, FCC2 phase and r phase in the alloy is 51.3 %, 32.3 % and 16.4 %, respectively. Compared with the sintered alloy, the relative content of FCC1 phase in WC state alloy is about 11.1 % higher, but the relative content of FCC1 phase is about 11.6 % lower, and the relative content of FCC2 phase is not much different. Because the microhardness of the r phase is the highest, which contributes the most to the hardness improvement of the alloy, the microhardness of the heat-treated alloy is lower than that of the sintered alloy. It is expected to obtain higher mechanical properties by combining solution and aging or treating the alloy at a higher cooling rate.
- Zhao, R.F., Liang, Y.C., Ren,B., Jiang, A.Y., Liu, J.X., Zhang, B. Effect of elemental synergism on the mechanical behavior of CoCrCuFeMnNi high-entropy alloy system. Met. Mater. Int. 2023, https://doi.org/10.1007/s12540-023-01586-5
Comment 4: In conclusion section, describe what does it add to the subject area compared with other former published materials.
Response 4: In previously published materials, we investigated the age hardening behavior of as cast CuCr2Fe2MnNi high-entropy alloy and found that the r phase precipitation significantly increased the microhardness of the alloy. We also prepared CuCrFeMnNi high entropy alloy powder and bulk using mechanical alloying and hot pressing sintering processes. We found that the powder phase structure was FCC main phase+BCC secondary phase, and the phase structure of bulk was FCC1 main phase+FCC2 secondary phase+ r phase. The sintered alloy had a high hardness of 534 HV and an elongation of 9.8%. On the basis of preliminary work, this article conducts heat treatment on sintered CuCrFeMnNi, and then uses four cooling methods to study the influence of these four cooling methods on the microstructure and microhardness of the alloy after heat treatment. It is found that the four cooling methods do not change the phase structure of the alloy, but the relative content of each phase changes significantly, thereby affecting the microhardness. The microhardness of water-cooled alloys is the highest, but still lower than that of sintered alloys. Generally speaking, when the hardness of an alloy decreases, its plasticity often improves. Therefore, this study provides a reference for improving the strength and plasticity matching of sintered high-entropy alloys.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors.
The paper titled “Effect of cooling method on microstructure and microhardness of CuCrFeMnNi high-entropy alloy" has been revised by authors based on my comments. However, there are minor revisions as follows:
1. Please correct the writing of “50oC” to “50°C” [Line 112]. Please check on other section with the same writing.
2. Please correct the writing of “A bulk of Φ12.5 mm × 6 mm” to A bulk of Æ12.5 mm × 6 mm” [Line 118].
3. Response no. 5 should be written in the paper in the appropriate part in the introduction or results and discussion.
I accept the paper with minor revision. Thanks to the author's effort to revise the paper.
Kind regards,
Author Response
Coatings
Editorial Office
Dear editors,
Thanks for your great efforts and reviewers’ thoughtful comments, all of which have been incorporated into the revised manuscript. Detailed descriptions are listed as follows and marked by red color in the revised manuscript (with marked).
Reviewer 1
Comment 1: Please correct the writing of “50oC” to “50°C” [Line 112]. Please check on other section with the same writing.
Response 1: According to Comment 1, we have corrected the above errors and thoroughly checked and corrected the subscript and superscript errors that appeared in the paper.
Comment 2: Please correct the writing of “A bulk of Φ12.5 mm × 6 mm” to A bulk of Æ12.5 mm × 6 mm” [Line 118].
Response 2: The revised manuscript has been revised according to the requirements of Comment 2.
Comment 3: Response no. 5 should be written in the paper in the appropriate part in the introduction or results and discussion.
Response 3: Add the content of response no. 5 to the appropriate section of the revised manuscript as requested in comment 3.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsWhile this manuscript is improved, it lacks any material testing and assessment for the alloy configurations that were cooled with different conditions. As a result, this work cannot be accepted.
Author Response
Coatings
Editorial Office
Dear editors,
Thanks for your great efforts and reviewers’ thoughtful comments, all of which have been incorporated into the revised manuscript. Detailed descriptions are listed as follows and marked by red color in the revised manuscript (with marked).
Reviewer 2
Comment: While this manuscript is improved, it lacks any material testing and assessment for the alloy configurations that were cooled with different conditions. As a result, this work cannot be accepted.
Response: The reviewer has provided 9 comments on this paper, and we would like to express our gratitude for your hard work and dedication. We responded to each of these 9 comments in the first round of responses. Among them, regarding the seventh and ninth comments, we did not respond positively, but both explained the reasons for not being able to correct them as required. However, the reviewer's rejection of the paper based on this is considered unfair. We believe that scientific research should be based on a key scientific problem to clarify phenomena and mechanisms, while the reviewers believe that we should conduct research on mechanical properties, corrosion performance, and wear performance, covering all aspects. It is difficult to do so due to limitations such as experimental equipment, research funding, and the energy of researchers. Therefore, we earnestly request Reviewer 2 to objectively and fairly evaluate the paper.
Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
Comments and Suggestions for AuthorsI appreciate the time and effort invested by the authors to improve this work. The main weakness of this work is the limited results. The authors conducted XRD, SEM and microhardness with only 7 figures, 5 of them being SEM images. Unfortunately, this is not enough to publish a paper.
Unfortunately, research funding or the...energy of the researchers is not one of the criteria taken into account when a manuscript is being assessed. A work needs to be complete with materials characterization and materials testing, as the other high quality manuscripts published in Coatings.
I would suggest to the authors to conduct more experiments on materials testing, expand and improve the manuscript and resubmit.
Author Response
Comment: I appreciate the time and effort invested by the authors to improve this work. The main weakness of this work is the limited results. The authors conducted XRD, SEM and microhardness with only 7 figures, 5 of them being SEM images. Unfortunately, this is not enough to publish a paper. Unfortunately, research funding or the...energy of the researchers is not one of the criteria taken into account when a manuscript is being assessed. A work needs to be complete with materials characterization and materials testing, as the other high quality manuscripts published in Coatings. I would suggest to the authors to conduct more experiments on materials testing, expand and improve the manuscript and resubmit.
Response: Thank you again to Reviewer 2 for reviewing this paper. As you mentioned, the results of this paper are indeed limited, and the experimental work is not rich enough. Due to the thin and small size of our experimental samples, it is not possible to test and analyze their compression, tensile, and other properties. Due to the weak magnetism of CuCrFeMnNi alloy, it is not possible to take clear photos at high magnification when observing and analyzing under tungsten filaments. Please understand. In subsequent research, we will appropriately select a high entropy alloy system and systematically and thoroughly study the effects of cooling rate, solid solution+aging and other heat treatment conditions on the microstructure, mechanical properties, corrosion performance, and friction and wear performance of high entropy alloys.
