Enhancing Surface Properties of Cu-Fe-Cr Alloys through Laser Cladding: The Role of Mo and B4C Additives
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsComments for author File: 
Comments.pdf
Author Response
We thank reviewer 1 for his comments. The authors have completely revised this review. The detailed revisions are in the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsRecommendation: The manuscript may require a minor revision in order to be accepted for publication
Comments:
The author presents "liquid phase separation phenomena of Cu-Fe-Cr alloys properties changes ability by adding Mo and B4C. The articles provide a systematic fabrication process and certified analytical confirmation may be convincing. Therefore, it is recommended that this manuscript be published in "coatings" after minor revisions. It should address the following points.
1. From Figure 13, it can be seen that the wear resistance decreases slightly with addition of B4C. The B4C model should achieve a good balance between wear resistance and impact toughness. What is the volume fraction, weight loss, and impact stiffness/toughness of the system in response to the original addition?
2. Why is it selected 4% of Mo and 2% of B4C? What are the effects of high and low addition of Mo and B4C?
3. It would be better to tabulate the parameters used and relative improvements with previous results.
4. XRD analysis was suggested to support the structural phase identification for Cu-Fe-Cr, Cu-Fe-Cr-Mo, and Cu-Fe-Cr-Mo-B4C alloys
5. Figure 3a-b splits on page 4 and 3c-f on page 5. Make sure Figure 3 is prepared as a single frame.
Comments on the Quality of English LanguageRecommendation: The manuscript may require a minor revision in order to be accepted for publication
Comments:
The author presents "liquid phase separation phenomena of Cu-Fe-Cr alloys properties changes ability by adding Mo and B4C. The articles provide a systematic fabrication process and certified analytical confirmation may be convincing. Therefore, it is recommended that this manuscript be published in "coatings" after minor revisions. It should address the following points.
1. From Figure 13, it can be seen that the wear resistance decreases slightly with addition of B4C. The B4C model should achieve a good balance between wear resistance and impact toughness. What is the volume fraction, weight loss, and impact stiffness/toughness of the system in response to the original addition?
2. Why is it selected 4% of Mo and 2% of B4C? What are the effects of high and low addition of Mo and B4C?
3. It would be better to tabulate the parameters used and relative improvements with previous results.
4. XRD analysis was suggested to support the structural phase identification for Cu-Fe-Cr, Cu-Fe-Cr-Mo, and Cu-Fe-Cr-Mo-B4C alloys
5. Figure 3a-b splits on page 4 and 3c-f on page 5. Make sure Figure 3 is prepared as a single frame.
Author Response
We thank reviewer 2 for his comments. The authors have completely revised this review. The detailed revisions are listed below:
Reviewer 2:
- From Figure 13, it can be seen that the wear resistance decreases slightly with addition of B4C. The B4C model should achieve a good balance between wear resistance and impact toughness. What is the volume fraction, weight loss, and impact stiffness/toughness of the system in response to the original addition?
Thank you for your comments and prompting us to discuss in detail the effect of adding B4C on the wear resistance and impact toughness of Cu-Fe-Cr-Mo- B4C alloys. The change in material properties with the addition of B4C is indeed multifaceted and has been evaluated in a number of tests.
For questions regarding the volume fraction of B4C, the authors have measured the amount of B4C in the alloy system by using the mass fraction. The specific mass fraction added to the Cu-Fe-Cr-Mo alloy here is 2%. This addition was optimised to improve wear resistance without adversely affecting impact toughness, which is critical for the intended application of the alloy.
Regarding weight loss, the authors reflected weight loss by measuring the volume of the grooves after wear. As shown in Figs. 14 and 16, both the steady-state friction coefficient and the groove volume of the Cu-Fe-Cr-Mo- B4C alloy decreased, demonstrating greater wear resistance. This improvement may be attributed to the uniform distribution of Fe-rich regions and Cu-rich matrix with the addition of B4C, as well as the change in the hardness difference between these regions.
As for impact stiffness/toughness, the authors have not yet carried out tests on impact toughness, but the enhanced wear resistance of Cu-Fe-Cr-Mo- B4C alloys based on friction coefficients and wear morphology analyses, as well as the homogeneity of the material structure presented in Figs. 2c and 3c, could also have a positive impact on impact toughness, but further testing is indeed needed to accurately quantify this effect. Thank you for your attention to this detail, and we will consider including additional mechanical property evaluations in future work to gain a more complete understanding of material properties.
- Why is it selected 4% of Mo and 2% of B4C? What are the effects of high and low addition of Mo and B4C?
Before choosing the ratio of 4% Mo and 2% B4C, the authors carefully examined the literature on the effect of adding Mo to similar alloy systems, such as the study conducted by Liu et al. (2017), which examined the effect of Mo on the microstructural and mechanical properties of TiC-NiTi metalloceramics. The addition of Mo apparently leads to significant changes in the microstructure and mechanical properties of the metal ceramics. In their study, up to 1.2 Vol% of Mo led to a decrease in porosity and an increase in the solubility of the binder phase, whereas additions above 1.8 Vol% led to the formation of a Mo-Ti solid solution phase without further decreasing the porosity. This suggests that there exists an optimum range of Mo additions within which beneficial effects can be achieved without detrimental phase changes or solubility saturation in the binder phase.
In the Cu-Fe-Cr-Mo- B4C alloy system, the authors used a higher percentage of molybdenum compared to the study by Liu et al. in order to take into account the different base materials (Cu-based alloys rather than Ni-Ti-based alloys) and the need to obtain sufficient hardness and strength in the Fe-rich region of the alloy. A Mo content of 4% was chosen to ensure the desired increase in mechanical properties while avoiding excessive molybdenum concentrations leading to brittleness or phase instability, as demonstrated by the saturation and formation of Mo-B clusters at higher molybdenum contents observed in the reference study.
Similarly, based on the known high hardness and ability to improve wear resistance, the authors set the addition of B4C at 2%. This is due to the known high hardness and wear resistance of B4C and its ability to refine the microstructure of the alloys. B4C also refines the grains and improves the homogeneity of the distribution of Fe-rich and Cu-rich regions. The authors also considered the risk of over-brittleness of the alloys, which may occur at higher B4C contents. The B4C content chosen is intended to improve the wear resistance of the alloy while maintaining an appropriate balance of mechanical properties, including toughness.
- It would be better to tabulate the parameters used and relative improvements with previous results.
The authors added performance comparisons with other related studies.
- XRD analysis was suggested to support the structural phase identification for Cu-Fe-Cr, Cu-Fe-Cr-Mo, and Cu-Fe-Cr-Mo-B4C alloys
The authors have added the XRD test results and analysed them in detail.
- Figure 3a-b splits on page 4 and 3c-f on page 5. Make sure Figure 3 is prepared as a single frame.
The author has adjusted the position of the image.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper presents the effects of Mo and B4C introduction in CuFeCr alloys deposited by laser cladding on a stainless-steel substrate. The aim is to define the role of Mo and B4C in modifying the liquid phase complex phenomena occurring during the laser treatment. The Authors deeply studied the morphological and chemical composition of the three alloys, developing a complex but convincing model. The analysis of the alloys’ microhardness, wear performances, and magnetic properties can be explained in terms of the proposed models. The discussion is verbose and not easily readable; nevertheless, the proposed claims and suggestions are self-consistent, and the scientific soundness is good. A few issues still must be addressed:
1. Figures: The Authors use a strange approach to the caption form; I suggest a scheme where letters are inserted in the figures or outside them, while the description is not below the figures but in the caption.
2. Results: Fig.2 is probably an optical image; the authors must better specify this. Lines 138-142: the CuFeCr alloy image is not commented (Fig.3a). Fig.4: the length bars are inconsistent.
3. Discussion: The JMatPro software and the parameters used must be introduced and carefully described in the experimental design section. Lines 370-372: There is no need to introduce iron, Fe, and copper, Cu, acronym. Figure 13: different colors should be used to improve clarity. Fig.16: the “a” panel is not specified.
Comments on the Quality of English LanguageEnglish quality is quite good, few typos are present.
Author Response
We thank reviewer 3 for his comments. The authors have completely revised this review. The detailed revisions are listed below:
Reviewer 3:
- Figures: The Authors use a strange approach to the caption form; I suggest a scheme where letters are inserted in the figures or outside them, while the description is not below the figures but in the caption.
The authors have modified the presentation of the figure captions. The letters are now located below the sub-pictures and their corresponding descriptions are placed in the figure captions.
- Results: Fig.2 is probably an optical image; the authors must better specify this. Lines 138-142: the CuFeCr alloy image is not commented (Fig.3a). Fig.4: the length bars are inconsistent.
The authors emphasise the fact that Figure 2 was taken by a light microscope. The authors have also corrected the error in which "Fig. 3a" in the original Fig. 3 was incorrectly labelled as "Fig. 3c", and have added some comments. The author has also corrected the length bar in Figure 5b(Original Figure 4b).
- Discussion: The JMatPro software and the parameters used must be introduced and carefully described in the experimental design section. Lines 370-372: There is no need to introduce iron, Fe, and copper, Cu, acronym. Figure 13: different colors should be used to improve clarity. Fig.16: the “a” panel is not specified.
The authors added details of the JMatPro setup in the Design of Experiments section. The author has changed the presentation of Figure 13 (Now Figure 14) and replaced the curve colour colours to make it clearer. The authors have also corrected the presentation related to iron, copper, etc. The authors have also corrected panel (a) in Figure 16 (Now Figure 17).
Reviewer 4 Report
Comments and Suggestions for AuthorsReferee’s Report on Ms: coatings-2725810-v1
Title: Liquid phase separation phenomena of Cu-Fe-Cr alloys and changes in properties with the addition of 4% Mo and 2% B4C
by Boxue Song, Xingyu Jiang and Zisheng Wang
Cu-Fe alloys possess excellent electrical and thermal conductivity, magnetism, and mechanical and wear resistance characteristics which can be adjusted by varying the Cu and Fe content and adding other components to suit particular applications. In this sense, the topic of this article is very relevant and the research results are of interest to be published. The authors prepared Cu-Fe-Cr-Mo and Cu-Fe-Cr-Mo-B4C composite coatings by laser cladding undercooling and conducted a comprehensive study of the microstructure, surface topography and the impact of Mo and B4C additions on macroscopic phase separation characteristics. The article is very well organized, the experiments are systematized and discussed in detail and clearly. It is written in good English and easy to read.
I have only a few minor remarks concerning the technical layout of the article which do not diminish its value:
1. Fig. 3a corresponds to "Fe core distribution of Cu-Fe-Cr alloys" but it is denoted as "c" and thus there is two "c" in Fig. 3. Please correct this error.
2. The presented Phase diagram (Fig. 7) in the article is taken from other authors, but their article is not cited in the corresponding figure.
3. Instead of "Mo's influence", "Mo's impact", "Figure 2b's results", etc. it is more correct to write "the influence of Mo", "the impact of Mo", "the results in Fig. 2b", etc ., respectively.
4. Lines 399-402; It would be better if the numbering of chemical equations (1-4) follows the equation numbering originally given and, therefore eqs. 1-4 would be eqs. 7-10.
10Mo+B4C ® 4Mo2B + Mo2C (7)
B4C ® 4B + C (8)
2Mo+B ® Mo2B (9)
2Mo+C ® Mo2C (10)
5. Lines 410- 412; [Bm]sm appears in eq. 7, but in the text this is given as [Bn]sn. Which of the two is correct?
6. Designation of a chemical must be correctly written. Please put the corresponding number of atoms in a subscript.
- Fe48Cu48Si4: line 40,
- Co40Fe40Cu20: line 49,
- Cu95Fe5 and Cu0.6(FeCrC)0.4]100-xSix: lines 56-57
- Cu88Fe12: line 471
- B4C: in the title, lines 86, 92, 191, lines 245-246, 275, 305, 322, 348, 357, 392, 399, 455-458, 461, 469, 473, 474, 517, 518, 540, 543, 545, 553, 556, 568, 570, 574, 578, 581, 582, 593, 597, 600.
- In the references: 6,10,12,13,15,20,29,40,47
7. Journal pages are missing from the following citations: 12,14,32,33,35,36,40,44,47.
8. Please, pay attention to the proper spacing. Use the spell-check option.
Comments for author File: Comments.pdf
Author Response
We thank reviewer 4 for his comments. The authors have completely revised this review. The detailed revisions are listed below:
Reviewer 4:
- Fig. 3a corresponds to "Fe core distribution of Cu-Fe-Cr alloys" but it is denoted as "c" and thus there is two "c" in Fig. 3. Please correct this error.
The author has corrected this error.
- The presented Phase diagram (Fig. 7) in the article is taken from other authors, but their article is not cited in the corresponding figure.
The authors added relevant reference.
- Instead of "Mo's influence", "Mo's impact", "Figure 2b's results", etc. it is more correct to write "the influence of Mo", "the impact of Mo", "the results in Fig. 2b", etc., respectively.
The authors have corrected a similar formulation.
- Lines 399-402; It would be better if the numbering of chemical equations (1-4) follows the equation numbering originally given and, therefore eqs. 1-4 would be eqs. 7-10.
The authors followed the reviewer's suggestion to make the numbering of chemical equations follow the numbering of formulas.
- Lines 410- 412; [Bm]sm appears in eq. 7, but in the text this is given as [Bn]sn. Which of the two is correct?
The author has corrected the error here.
- Designation of a chemical must be correctly written. Please put the corresponding number of atoms in a subscript.
-Fe48Cu48Si4: line 40,
-Co40Fe40Cu20: line 49,
-Cu95Fe5 and Cu0.6(FeCrC)0.4]100-xSix: lines 56-57
-Cu88Fe12: line 471
-B4C: in the title, lines 86, 92, 191, lines 245-246, 275, 305, 322, 348, 357, 392, 399, 455-458, 461, 469, 473, 474, 517, 518, 540, 543, 545, 553, 556, 568, 570, 574, 578, 581, 582, 593, 597, 600.
- In the references: 6,10,12,13,15,20,29,40,47
We thank the reviewers for the thorough and careful review. The authors have thoroughly checked and corrected the above errors. Also for reference 6 and reference 40 (now updated to reference 41), Ni204 and Ti6Al4V refer to the grades of Ni-based alloy powders and titanium-based alloy powders, respectively, and therefore the authors have made no changes.
- Journal pages are missing from the following citations: 12,14,32,33,35,36,40,44,47.
The authors have updated the journal page numbers of the relevant references.
- Please, pay attention to the proper spacing. Use the spell-check option.
The authors have adjusted the relevant spacing.
