Laser Beam Welding of a Low Density Refractory High Entropy Alloy
, Nikita Stepanov 1, Gennady Salishchev 1, Volker Ventzke 2, René Dinse 2 and Nikolai Kashaev 2Round 1
Reviewer 1 Report
The authors studied the effects of pre-heating of Ti1.89NbCrV0.56 refractory high entropy alloy prior to laser welding. The paper is well written and interesting. The results are good and worth publishing. The authors should however consider the following points.
Review comments
The authors should write most of the initials (such as BM, RT, FZ) in full, as much as possible, to make the paper readable.
Abstract: Revise this section to clearly state the actual aim of the study, i.e. effects of pre-heating prior to laser welding.
Line 77: Quantify the term clear shiny surfaces. What was the surface roughness after mechanical polishing?
Line 85: What was the laser wavelength and the beam quality?
Page 12: The explanation given for the variation of the results presented in Figure 9, for the cases of 400˚C, 600˚C and 800˚C, is not satisfactory.
The results show considerable variation in the cases of 600˚C and 800˚C. Figure 2 shows that there were no cracks in both cases of 600˚C and 800˚C.
Line 289: I believe the last word in this line should be increase and not decrease.
Author Response
First, we would like to thank all reviewers for their hard work and useful comments. The detailed response is given below, the changes in the manuscript are highlighted with yellow color.
Response to Reviewer 1 Comments
Point 1: The authors should write most of the initials (such as BM, RT, FZ) in full, as much as possible, to make the paper readable.
Response 1: Thank you for your comment. Abbreviations were disclosed in the text to improve readability.
Point 2: Abstract: Revise this section to clearly state the actual aim of the study, i.e. effects of pre-heating prior to laser welding.
Response 2: The abstract was revised in accordance with the suggestion.
Point 3: Line 77: Quantify the term clear shiny surfaces. What was the surface roughness after mechanical polishing?
Response 3: The average arithmetic mean deviation of the assessed profile, Ra measured according to the ISO 1997 was 1.8 µm.
Point 4: Line 85: What was the laser wavelength and the beam quality?
Response 4: Butt joint LBW was performed using an 8.0 kW continuous wave ytterbium fiber laser with a fiber optic (300 µm core diameter, 300 mm focal length, 120 mm collimation lens and 750 µm focus diameter). The wavelength of the laser was 1070 nm and the resulting beam parameter product was 10.6 mm × mrad. Corresponding information was added in the Materials and methods section.
Point 5: Page 12: The explanation given for the variation of the results presented in Figure 9, for the cases of 400˚C, 600˚C and 800˚C, is not satisfactory. The results show considerable variation in the cases of 600˚C and 800˚C. Figure 2 shows that there were no cracks in both cases of 600˚C and 800˚C.
Response 5: We do agree with you – the absence of cracks itself can’t explain the increased ductility, yet it is for sure the required condition to get reasonable ductility. We believe that increase in ductility is also due to the precipitation of the Laves phase particles after welding at 800˚C. We have provided a corresponding explanation in the last by one paragraph in the discussion (lines 292-301). We have modified this paragraph slightly to make our ideas clearer to the reader.
Point 6: Line 289: I believe the last word in this line should be increase and not decrease.
Response 6: We are sorry for this slip, the word "increase" is now used in the article
Reviewer 2 Report
The study is quite interesting and well presented. However, there is the need of some corrections of the grammar and syntax. Finally, the authors could consider to accept some suggestions inserted into the commented pdf file.
Comments for author File: 
Comments.pdf
Author Response
First, we would like to thank all reviewers for their hard work and useful comments. The detailed response is given below, the changes in the manuscript are highlighted with yellow color.
Response to Reviewer 2 Comments
Point 1: Reviewer suggested making corrections to the text.
Response 1: Suggested corrections were made.
Point 2 Figure 1a: The region from which the close-up was extracted should be specified in the larger scale image.
Response 2: The figure was modified in accordance with suggestions.
Point 3: Line156: Did the authors clarified the method of measuring these structural features?
Response 3: We have used the linear intercept method. Corresponding information was added to the Materials and methods section.
Reviewer 3 Report
The title and the abstract of the paper are consistent with its content. The conclusions are well sustained by the content of the paper.
Please check the following issues:
Line 87: Is the value 0.0 mm correct?
Line 120: Is the reference to Figure 7 correct or should be replaced by Figure 9?
The paper can be accepted for publishing, after some minor revisions of the English language. For example:
Line 175: "Weld zone" should be replaced by "welding zone". Please also check some other occurrences of the "weld" term in the text
There are several places in the manuscript where the article "a /an" should be removed or replaced by "the". For example:
Line 110: "a loading speed" should be replaced by "the loading speed".
Please avoid using "a / an" in front of the name of equipment items.
etc.
Author Response
First, we would like to thank all reviewers for their hard work and useful comments. The detailed response is given below, the changes in the manuscript are highlighted with yellow color.
Response to Reviewer 3 Comments
Point 1: Line 87: Is the value 0.0 mm correct?
Response 1: It is correct. This means that the focus was exactly on the surface
Point 2: Line 120: Is the reference to Figure 7 correct or should be replaced by Figure 9?
Response 2: We are sorry for this slip. The reference to Figure 7 was replaced.
Point 3: Line 175: "Weld zone" should be replaced by "welding zone". Please also check some other occurrences of the "weld" term in the text
Response 3: Thank you for your comment. The term "weld zone" has been replaced by the term "welding zone" through the text. We have also checked how the term “weld” was used through the text.
Point 4: There are several places in the manuscript where the article "a /an" should be removed or replaced by "the". For example: Line 110: "a loading speed" should be replaced by "the loading speed". Please avoid using "a / an" in front of the name of equipment items.
Response 4: We have checked the usage of the definite and indefinite articles through the text and made some corrections, including the ones suggested by the reviewer.
