Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Paper No.: metals-3096396

Title:  Enhanced strength-ductility combination in laser welding of CrCoNi medium-entropy alloy with ultrasonic assistance

There are some notes that should be treated.

1-       In line 38: “However, the combination of mechanical properties is not desirable”. This standalone statement is meaningless. Please revise.

2-       In line 39: “For example, Peng et al. [51] reported that EB welded NiCoCrAl3Ti3 joints showed high tensile strength …….”. the abbreviation “EB” is not previously explained. Please explain it.

3-       Please describe the work (lines 46 and 49) in third person.

4-       The last paragraph in the introduction (lines 46-53) is suitable as abstract not as aim of the work.

5-       In line 58 “Figure 11(a) indicates that …..”. please change Figure 11 to Figure 1.

6-       In the “Materials” please provide the chemical composition of the investigated material. In this part it is better to introduce the study material and its processing and production regime.

7-      . In the welding process, please describe the sample geometry.

8-       The of the title of the y-axis needs revision it can’t be in (mm). Moreover, Figure 4 is not explained in the manuscript text. Please include it explanation.

9-       In figure 7, please use annotation to describe the different 5 images.

10-  For Figures 8-10, make a schematic description to indicate the position of the analyzed region in the welded joint.

11-   Please indicate if the mentioned references ([51-53, 67-75]) in Figure 12 for the similar materials.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The entire research problem is interesting and is very well presented in the article. Despite the very good quality of the work, I suggest making a few corrections, which in mu opinion much more improve the quality of this work:

#1 Figure 2 - Replace the name "air supply device" by "shielding gas supply device", "laser" by "laser beam"  and correct "cibration" to "vibration"

#2 lines 83-84 - There is no Table 4-1, but Table 1.

#3 lines 113- 115 - There is no Figure 3e in this work, rather Figure 4. Moreover, we use "face and root of the weld/joint" - not "front and back melt" or "top and bottom". Wrong nomenclature. 

#4 Figure 3 caption - Watt must be "W", not "w"

#5 Figure 4 - Firstly, see and apply remark #3. "Melting width is in [mm] - wrong order of magnitude of the unit (eg. 3000 mm). Delete lines between the numbers of processes, because  because the results represented are not dependent on one variable, but on various factors. The lines suggest a mathematical relationship to one independent variable. These results can also be presented in the form of, for example, a bar chart.

#6 In the article is no information about the vibration frequency

#7 Figure 6 caption - the words should be lowercase. Point 3.1.3 title - using capital letter.

#8 lines 168-171 The described grain growth mechanism is incorrect. The crystals grow from the fusion line towards the center, and when the entire weld pool cools significantly, the crystals begin to nucleate throughout the entire volume (best seen in Fig. 5b). See: https://www.slideshare.net/slideshow/welding-metallurgy-ferrous-materials-pdf/269604765#60
Description that "grains are disadvantaged in the competitive mechanism of grain growth" is very controversial. The grain refinement is very important to the increase of strength properies and desirable in the structure.

#9 Figure 7. lines 174-182 - Central line in the fusion zone (Fig. 7) is an evidence that cristalization proces ended in this place (line), not started. Thus the mechanism of cristalisation described in lines 174-182 is not proper. The lowest tempertaure is in regions which are closer to solid state and it is direction of energy (temperature) flow - from liquid to solid state. Mechanism description must be corrected.

#10 Figures 8-10 and line 199 - What was the error in measuring the chemical composition? Place this informacion in table whimthem. comp.

#11 Lines 268-269 The sentence "The tensile strength of the joints increased from 686 MPa and 886 MPa." looks like not ended. It has not sense in comparition with data placed in Table 2.

#12 Figure 12a - Temperature is 300K, but in Table 2 and in text is 293K.

#13 Lines 291-293 - See remarks #8 and #9

#14 "Author Contributions, Data Availability Statement, Conflicts of Interest" are not filled!

#15 In the article are numerous inadequate references.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have treated the raised issues by the reviewer.