The Effect of Laser Power on the Microstructure and Wear Resistance of a Ni3Al-Based Alloy Cladding Layer Deposited via Laser Cladding
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper by Cai et al is about the influence of laser power on microstructure and wear resistance of Ni3Al alloys cladding layers with chromium carbide (Cr7C3). The coatings were prepared by laser cladding technique. The authors shown that the increase of laser power resulted in decrease of hardness and increase of wear rate of cladding layers. The paper can serve to be published after minor corrections needed for Figure 14. In this figure, the authors should change Chinese language in a legend to English one. I speak about differences between red and green bars, because one cannot establish what a difference between the bars from the text describing Figure 14.
Author Response
Manuscript ID: coatings-2892676
The effect of laser power on the microstructure and wear resistance of a Ni3Al-based alloy cladding layer deposited via laser cladding
Dear Reviewer,
Thank you very much for your comments on the manuscript entitled “The effect of laser power on the microstructure and wear resistance of a Ni3Al-based alloy cladding layer deposited via laser cladding” (coatings-2892676). The comments are highly appreciated and we have revised the paper in accordance with the suggestions.
The answers to your comments are written in the following pages.
Thank you and best regards.
Sincerely yours,
Yihui Cai
School of Materials Science and Engineering, Tianjin University of Technology
Email: caiyihui@stud.tjut.edu.cn
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PLEASE GO TO THE NEXT PAGE FOR OUR RESPONSE TO THE COMMENTS
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Response to Reviewer 1 Comments
Point 1: The paper by Cai et al is about the influence of laser power on microstructure and wear resistance of Ni3Al alloys cladding layers with chromium carbide (Cr7C3). The coatings were prepared by laser cladding technique. The authors shown that the increase of laser power resulted in decrease of hardness and increase of wear rate of cladding layers. The paper can serve to be published after minor corrections needed for Figure 14. In this figure, the authors should change Chinese language in a legend to English one.
Response 1: Sorry for the errors. we have revised the Figure 14 as follows.
Figure 14. Wear rates of cladding layer samples with different laser powers.
Point 2: I speak about differences between red and green bars, because one cannot establish what a difference between the bars from the text describing Figure 14.
Response 2: We thank the reviewer for the suggestion. We have revised the manuscript according to the comments. We revised the manuscript as follows.
(Line 390-396) Figure 14 shows the wear rates of the laser cladding layer samples and the grinding disks under different laser power conditions. It can be found that the wear rates of cladding layer samples after friction and wear test is much less than that of grinding disks. With the increase of laser power, the wear rates of the cladding layer samples and the grinding disks changes in the same trend. When the laser power was 1.8 kW, the wear rate of the laser cladding layer was 0.832×10-5 mm3/N·m. With an increase in laser power to 2.0 kW, the wear rate of the laser cladding layer decreased to 0.480×10-5 mm3/N·m.
Reviewer 2 Report
Comments and Suggestions for AuthorsStrengths
The authors show in this work, laser cladding layers with different laser powers were prepared using laser cladding technology, and their microstructure and wear resistance were studied. The following conclusions were reached:
(1) The laser cladding layer of a Ni3Al-based alloy prepared via laser cladding was well formed, and the laser cladding layer and the matrix showed metallurgical bonding. There were no pores, cracks, or other defects in the laser cladding layer. With an increase in laser power from 1.8 kW to 2.4 kW, the dilution rate of the laser cladding layer increased from 4.12% to 8.87%.
(2) The microstructure of the Ni3Al-based alloy laser cladding layer was mainly γ'-Ni3Al, β'-NiAl, and in situ autogenous Cr7C3, and the carbides were dispersed in the laser cladding layer. With an increase in laser power from 1.8 kW to 2.4 kW, the average size of the carbides in the laser cladding layer increased from 1.51 μm to 2.23 μm and the area proportion of the carbides in the laser cladding layer decreased from 28.08% to 27.25%.
(3) The Ni3Al-based alloy laser cladding layer had excellent wear resistance. With an increase in laser power, the wear resistance of the Ni3Al-based alloy laser cladding layer first increased and then decreased. When the laser power was 2 kW, the laser cladding layer had the best wear resistance. The friction coefficient was 0.29, and the wear rate of the laser cladding layer was 0.416×10-5 mm3/N·m. Moreover, the laser cladding layer of the Ni3Al-based alloy prepared with a laser power of 2 kW was more friendly to gray cast iron, and the loss rate of gray cast iron to the grinding disk was only 1.669×10-5 mm3/N·m.
An excellent achievement of the authors is the science-based approach to optimally determine the laser power of 2 kW.
The authors have presented a good contemporary literary review.
Weakness
1. In Table 1, give the values of P and B in a single line.
2. Equation 1, not Formula 1.
3. Figure 4 (d) 2.4 kW, not (b) 2.4 kW, and Figures 7, 15, 16, too.
4. Figure 7 appears before it is mentioned in the text.
5. Figure 14. Change the symbols of laser cladding layer samples and grinding disks from hieroglyphics to English text.
Comments for author File: 
Comments.pdf
Author Response
Manuscript ID: coatings-2892676
The effect of laser power on the microstructure and wear resistance of a Ni3Al-based alloy cladding layer deposited via laser cladding
Dear Reviewer,
Thank you very much for your comments on the manuscript entitled “The effect of laser power on the microstructure and wear resistance of a Ni3Al-based alloy cladding layer deposited via laser cladding” (coatings-2892676). The comments are highly appreciated and we have revised the paper in accordance with the suggestions.
The answers to your comments are written in the following pages.
Thank you and best regards.
Sincerely yours,
Yihui Cai
School of Materials Science and Engineering, Tianjin University of Technology
Email: caiyihui@stud.tjut.edu.cn
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PLEASE GO TO THE NEXT PAGE FOR OUR RESPONSE TO THE COMMENTS
-------------------------------------------------------------------------------------------------------
Response to Reviewer 2 Comments
Point 1: In Table 1, give the values of P and B in a single line.
Response 1: According to the standard table layout format, while considering the aesthetics of the table, we suggest not changing it.
Point 2: Equation 1, not Formula 1.
Response 2: Sorry for the errors. We revised the manuscript as follows:
(Line 146-147) The wear rate (δ) of the wear pin and the grinding disk was calculated according to Equation 1:
Point 3: Figure 4 (d) 2.4 kW, not (b) 2.4 kW, and Figures 7, 15, 16, too.
Response 3: We thank the reviewer for the serious and responsible. We have revised the manuscript according to the comments. We revised the manuscript as follows:
(Line 194-195) Figure 4. Macroscopic morphology of cross-section of single-pass laser cladding layer: (a) 1.8 kW, (b) 2.0 kW, (c) 2.2 kW, and (d) 2.4 kW.
(Line 262-263) Figure 7. Carbide organization in laser cladding layers prepared at different laser powers: (a) 1.8 kW, (b) 2.0 kW, (c) 2.2 kW, and (d) 2.4 kW.
(Line 457-458) Figure 15. Different laser power preparations of Ni3Al-based alloy laser cladding layers and their wear morphologies (secondary electron imaging): (a) 1.8 kW,（b) 2.0 kW, (c) 2.2 kW, and (d) 2.4 kW.
(Line 461-462) Figure 16. Wear morphologies of Ni3Al-based alloy laser cladding layers prepared with different laser powers (backscattering electron imaging): (a) 1.8 kW,（b) 2.0 kW, (c) 2.2 kW, and (d) 2.4 kW.
Point 4: Figure 7 appears before it is mentioned in the text.
Response 4: We move Figure 7 after the relevant description, We revised the manuscript as follows:
(Line 245-263) Figure 7 shows the sizes and distributions of carbides in the laser cladding layers of the Cr7C3/Ni3Al alloy powder prepared at different laser powers. It can be seen in the figure that the Cr7C3 particles in the laser cladding layer gradually became larger with the increase in laser power, and short rod-shaped and irregular carbides formed. As can be seen in Figure 7a, when the laser power was 1.8 kW, the particle size of Cr7C3 was relatively small, the shape was mainly elliptical, and the particles were dispersed in the laser cladding layer. It can be observed in Figure 7b that when the laser power was 2 kW, a small amount of Cr7C3 particles in the laser cladding layer became larger, and their shapes were mainly oval and polygonal. When the laser power was increased to 2.4 kW, the carbide morphology and size changed greatly. As can be seen in Figure 7d, short rod-shaped Cr7C3 particles appeared in the laser cladding layer, the elliptical carbides merged and grew into irregularly shaped carbides, and the size of the carbides increased significantly. The heat input of the laser cladding layer increased with the increase in laser power. At the same time, the diffusion capacity of fine Cr7C3 grains increased, resulting in the merging and growing of Cr7C3 particles.
Figure 7. Carbide organization in laser cladding layers prepared at different laser powers: (a) 1.8 kW, (b) 2.0 kW, (c) 2.2 kW, and (d) 2.4 kW.
Point 5: Figure 14. Change the symbols of laser cladding layer samples and grinding disks from hieroglyphics to English text.
Response 5: Sorry for the errors. we have revised the Figure 14 as follows.
Figure 14. Wear rates of cladding layer samples with different laser powers.
Reviewer 3 Report
Comments and Suggestions for AuthorsIn this paper the effect of laser power on the properties of Ni3Al-based alloy cladding layer deposited via laser cladding was studied. The article has scientific novelty and practical significance. It will be useful to other researchers.
The positive points of the article are:
1. Analysis of publications made on this topic, which contains 33 studies, most of which are up to date. Also, the scope of the paper is clearly presented at the end of the introduction.
2. Very detailed and high-quality description of the test powder obtaining process and also of the research methodology.
3. Scientifically substantiated, argued and detailed results and discussions
4. The conclusions drawn from the research results are formulated concisely and reflect the essence of the research.
I recommend the article for publication and I express my gratitude to the authors for the high level of research and the high quality of the presentation of the results, with only small observations:
- error bars on hardness (but not only) chart could be helpful
- the legend within figure 14 is not in English
- a personal curiosity: what was the criteria for choosing 48N loading for the mechanical testing (maybe I missed that information)
In this paper the effect of laser power on the properties of Ni3Al-based alloy cladding layer deposited via laser cladding was studied. The article has scientific novelty and practical significance. It will be useful to other researchers.
The positive points of the article are:
1. Analysis of publications made on this topic, which contains 33 studies, most of which are up to date. Also, the scope of the paper is clearly presented at the end of the introduction.
2. Very detailed and high-quality description of the test powder obtaining process and also of the research methodology.
3. Scientifically substantiated, argued and detailed results and discussions
4. The conclusions drawn from the research results are formulated concisely and reflect the essence of the research.
I recommend the article for publication and I express my gratitude to the authors for the high level of research and the high quality of the presentation of the results, with only small observations:
- error bars on hardness (but not only) chart could be helpful
- the legend within figure 14 is not in English
- a personal curiosity: what was the criteria for choosing 48N loading for the mechanical testing (maybe I missed that information)
Author Response
Manuscript ID: coatings-2892676
The effect of laser power on the microstructure and wear resistance of a Ni3Al-based alloy cladding layer deposited via laser cladding
Dear Reviewer,
Thank you very much for your comments on the manuscript entitled “The effect of laser power on the microstructure and wear resistance of a Ni3Al-based alloy cladding layer deposited via laser cladding” (coatings-2892676). The comments are highly appreciated and we have revised the paper in accordance with the suggestions.
The answers to your comments are written in the following pages.
Thank you and best regards.
Sincerely yours,
Yihui Cai
School of Materials Science and Engineering, Tianjin University of Technology
Email: caiyihui@stud.tjut.edu.cn
-------------------------------------------------------------------------------------------------------
PLEASE GO TO THE NEXT PAGE FOR OUR RESPONSE TO THE COMMENTS
-------------------------------------------------------------------------------------------------------
Response to Reviewer 3 Comments
Point 1: Error bars on hardness (but not only) chart could be helpful
Response 1: We thank the reviewer for the suggestion. We have revised the Figure 12 according to the comments. We revised the manuscript as follows：
Figure 12. Average microhardness of the laser cladding layer at different laser powers.
Point 2: the legend within figure 14 is not in English
Response 2: Sorry for the errors. we have revised the Figure 14 as follows.
Figure 14. Wear rates of cladding layer samples with different laser powers.
Point 3: A personal curiosity: what was the criteria for choosing 48N loading for the mechanical testing (maybe I missed that information)
Response 3：In the previous study, we tried low loading and high loading as test conditions. It is found that the instantaneous friction coefficient fluctuates greatly under the low load of 24N, and the laser cladding layer has almost no mass loss, because the lower contact pressure cannot remove the abrasive dust of the grinding disks in time, and has little influence on the surface of the laser cladding layer. When we used 60N load, the contact surface of gray cast iron disk is seriously damaged, and the error of the disk loss rate obtained by repeated tests is large, and the experimental data are not reliable. Then we referred to the research of some scholars on Ni3Al intermetallic compounds and Cr3C2 strengthened Ni3Al-based alloys. Karin Gong, from Chalmers University of Technology, is one of the first researchers to work on Ni3Al-based alloy. The contact pressure adopted in his article "Tribological evaluation on Ni3Al-based alloy and its composites under unlubricated wear condition" is 2.83 MPa and 5.66 MPa. In communication with him, Fu, a Chinese scholar who also studied Ni3Al-based alloy, used the contact pressure of 8 MPa as the friction test condition for the first time in her article " Effects of Cr3C2 content and temperature on sliding friction and wear behaviors of Cr3C2/Ni3Al composite materials". Referring to research of Karin Gong and Lihua Fu, the load of 48 N (mean contact stress of about 8 MPa) was finally selected for the test in this paper.
