Effects of Water Cooling on the Microstructure of Electron Beam Additive-Manufactured Ti-6Al-4V

Round 1

Reviewer 1 Report

1. It was confused for the Figure 2, the structure of Figure 2(b)  is from which region?

2. Page2, line 73,74, the latter case should be with water cooling?

3. For Figure 2 and Figure 7, the auhtor need the describe more detail, i.e. Where is the metallographic structure sampling location? Longitudinal section or cross section?
4. The results of section 3.2 is very important to understand the role of water cooling of the TiAlV alloys, here need more basic information. Where is the sample sampling location? The closer the location is to the substrate, the faster the cooling rate is. The location away from the substrate has a relatively slow cooling rate. Different cooling rates will affect the microstructure of the material. Please indicate the location of sample sampling for OM, SEM and TEM analysis too.
5. .It is obvious that the acicular martensite is not prone to fragmentation, since the dislocations generated at one acicular surface easy reach other acicular boundary surface without forming a dislocation pile-up within the acicular martensite. (lines 377-380), Is there any evidences for this conclusion?

Author Response

We greatly appreciate the reviewer’s time for careful reading of the manuscript, helpful suggestions and valuable comments. All the changes made in the revised manuscript were highlighted by a yellow marker. We have also made some changes in the manuscript according to suggestions of another reviewer. The point-to-point responses to the reviewer’s comments are listed as following:

1. It was confused for the Figure 2, the structure is from which region?

Thank You for this relevant comment. The microstructure  of Figure 2(b)  is obtained from longitudinal direction (parallel to build direction) in the central part of the rectangular Ti-6Al-4V bar. The information has been added to the new version of the manuscript.

2. Page2, line 73,74, the latter case should be with water cooling?

Thank You for the careful reading. The “former” word is more correct. The mistake has been corrected.

3. For Figure 2 and Figure 7, the auhtor need the describe more detail, i.e. Where is the metallographic structure sampling location? Longitudinal section or cross section?

The information has been added to the manuscript.

4. The results of section 3.2 is very important to understand the role of water cooling of the TiAlV alloys, here need more basic information. Where is the sample sampling location? The closer the location is to the substrate, the faster the cooling rate is. The location away from the substrate has a relatively slow cooling rate. Different cooling rates will affect the microstructure of the material. Please indicate the location of sample sampling for OM, SEM and TEM analysis too.

The information of sampling location has been added to figure captures.

5. It is obvious that the acicular martensite is not prone to fragmentation, since the dislocations generated at one acicular surface easy reach other acicular boundary surface without forming a dislocation pile-up within the acicular martensite. (lines 377-380), Is there any evidences for this conclusion?

Unfortunately we have no references serving as evidence for this conclusion.

To avoid misinterpretation of the obtained results this phrase was omitted. The model of continuous dynamic recrystallization was presented instead. Nevertheless we will continue our efforts to confirm the effect of a lath thickness on the dislocation pile-up.

Reviewer 2 Report

Manuscript with number “metals-1430014” was reviewed, flowing comments are suggesting:

Please use the standard terminologies of ASTM/ISO 52900 for correct terminologies of the Additive Manufacturing processes.

The introduction section is very weak. Please improve it.

Please add the chemical composition of the material to a table.

Please add a direction of perimeter printing direction in figure 1.

Results have been just reported, please compare your finding with other researches.

It is also suggesting to compare your finding with other methods and clarify your research benefits related to other AM methods.

Following paper suggesting for introduction part and comparing results:

Ishfaq, Kashif, et al. "A review on the performance characteristics, applications, challenges and possible solutions in electron beam melted Ti-based orthopaedic and orthodontic implants.

Ding, Liping, et al. "Manufacturability analysis of extremely fine porous structures for selective laser melting process of Ti6Al4V alloy

Kulkarni, Janmejay Dattatraya, et al. "Microstructure evolution along build direction for thin-wall components fabricated with wire-direct energy deposition

Ettaieb, Kamel, Sylvain Lavernhe, and Christophe Tournier. "A flash-based thermal simulation of scanning paths in LPBF additive manufacturing

Please add economic study related to your work. The following paper suggested as an example:

Khorasani, Mahyar, et al. "Additive manufacturing a powerful tool for the aerospace industry

 

 

 

Author Response

Thank You for attentive reading and valuable comments. They have allowed to improve the manuscript a lot. Please find the replies below. We have also made some changes in the manuscript according to Your comments and suggestions of another reviewer. All the changes made in the revised manuscript were highlighted by a yellow marker.

1. Please use the standard terminologies of ASTM/ISO 52900 for correct terminologies of the Additive Manufacturing processes.

Thanks for Your valuable comments. Following Your recommendation terms have been corrected according to standard terminologies of ASTM/ISO 52900.

2. The introduction section is very weak. Please improve it.

Following Your recommendations, we have substantially rewritten the Introduction section.

3. Please add the chemical composition of the material to a table.

The Table has been added to the new version of the manuscript.

4. Please add a direction of perimeter printing direction in figure 1.

In our study, the trajectory of electron beam scanning path does not involve the perimeter line. The line indicates only the edges of 3D printed Rectangular Ti-6Al-4V bars. To avoid the misunderstanding, the perimeter line has been omitted from figure 1.

5. Results have been just reported, please compare your finding with other researches.

Thank You for this suggestion. The following items are presented in the new version of the manuscript:

- A comparative analysis of the cooling rate of the molten bath during EBAM. EBM and SLM,

- A comparative analysis of the microstructure and phase composition of the Ti-6Al-4V samples produced by EBAM. EBM and SLM,

- A comparative analysis of the microstructure and phase composition of our EBAM Ti-6Al-4V samples and similar EBAM Ti-6Al-4V samples produced by Xu, J. and co-authors [13],

- the effect of the water cooling of the build platform on the microstructure of the EBAM Ti-6Al-4V samples has been compares with the effect of the water environment during the underwater wire-feed laser deposition of the Ti-6Al-4V parts., etc.

6. It is also suggesting to compare your finding with other methods and clarify your research benefits related to other AM methods.

The information has been added to the manuscript.

7. Following paper suggesting for introduction part and comparing results:

Thank You for this suggestion.  In the new version of the manuscript 10 references has been added included the suggested by the reviewer.

8. Please add economic study related to your work. The following paper suggested as an example:

Prof. Shugurov A.R, as the Editor of Special Issue "Microstructure and Mechanical Properties of Titanium Alloys", does not recommend us to add economic study related to your work. According to Prof. Shugurov, this Special Issue is focused on various aspects of microstructure evolution in titanium alloy samples as well as on the relation between their microstructure and mechanical behavior. We absolutely agree that the economic study is not appropriate for the scope of the academic journal.

Round 2

Reviewer 1 Report

The response from authors could be accepted. It can be accepted for this version from myside.

Reviewer 2 Report

All comments have been done, the manuscript is ready for the publishing process.