Advancements and Prospects in Electro-Sinter-Forging
Round 1
Reviewer 1 Report
The article has a rather commercial tone and there is very little science involved. Major rewriting and restructuring are recommended before the paper can be considered for publication. Detailed feedback:
-In the introduction the author should current density and pressure instead of load and current.
-The flow and the organization of the manuscript requires major editing.
-In figures 1 and 3 the scale bars are missing.
- In the captions of the figures the capacitor discharge parameters should be disclosed.
-There are several issues with the reference management software “Error! Reference source not found..”
-Most of the figures are in low resolution and certainly not of publishing standard. Figure 7 is rather unclear and the scale bar is not legible.
-Many typos and poor writing: BiTe Bismuth Telluride; How big and which will exactly the markets be and the number and type of applications of this technology is hard to estimate; Is it possible to induce reactions with interstitial gases to create novel ceramic or composite materials?
- The author should obtain permission to reprint readily published figures. It is not clear which of the results are new.
Author Response
The article has a rather commercial tone and there is very little science involved. Major rewriting and restructuring are recommended before the paper can be considered for publication. Detailed feedback:
-In the introduction the author should current density and pressure instead of load and current.
Answer: A table of the specific energy inputs, starting pressure and max pressures was added in the introduction. Load and Current were also left as they are part of the technological characteristics of the machines that are currently available to execute the process. Just like specifying that a press can generate a certain level of force and have a certain stroke it is important to have an idea of the voltages, the currents, the energies in an electro-sinter-forging machine.
-The flow and the organization of the manuscript requires major editing.
Answer: The manuscript has been adjusted.
-In figures 1 and 3 the scale bars are missing.
Answer: In Figure 1 the size of the parts is now specified in the description. In Figure 3 the description gives the exact dimensions of the parts.
- In the captions of the figures the capacitor discharge parameters should be disclosed.
Answer: Done.
-There are several issues with the reference management software “Error! Reference source not found..”
Answer: the original version didn’t have any issue, the problem is fixed now, it was the reference to the images.
-Most of the figures are in low resolution and certainly not of publishing standard. Figure 7 is rather unclear and the scale bar is not legible.
Answer: High resolution pics are being added. Figure seven is reviewed to make it more clear and show the scale bar.
-Many typos and poor writing: BiTe Bismuth Telluride; How big and which will exactly the markets be and the number and type of applications of this technology is hard to estimate; Is it possible to induce reactions with interstitial gases to create novel ceramic or composite materials?
Answer: Market considerations added in the review. I do not understand the last question as I am posing it also in the paper. I have no answer as of today. We certainly have seen no oxidation up to know so I am keen to say that this will not be possible but I cannot exclude that working with reactive gasses and in high pressure this might not be possible.
- The author should obtain permission to reprint readily published figures. It is not clear which of the results are new.
Answer: Details specified in the revised manuscript. The table should clarify.
Thank you for the comments and help.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript deals with the recent advancements, the future prospects, and open issues of the Electro sinter forging (ESF) process. The author reports several examples regarding the use of ESF to prepare different materials (metals and alloys). I recommend the publication of this manuscript to be published in Metals with some changes listed below:
#1 In general, it is difficult to distinguish which results are the new results for this paper and which are the results from the previous studies. For the former case the author needs to give much more details of the sintering parameters and testing details, like, the energy used, the pressure, any die/punch were used…for example, the process parameters of the eForged 100Cr with near-net shape, the impact test details of stainless steels.
#2 the sectioning of the manuscript is confusing. For example, the Iron based and 100. Cr6-like composition are below metals, but tool steel/stainless steel are a new sections, parallel to metals and copper based. Please rearrange it.
#3 there are a lot of failed cross-references, please check.
#4 it is maybe better to put both of the curves in Fig5, for better comparison.
#5 the author states that avoiding “old” oxidized powders is critical to achieve good sintering quality. I think this is a common issue for powder metallurgy in general. Is there any specificity for ESF?
#6 please give a specific description of Fig7 in the caption. What are the three figures? and add also a scale.
Author Response
The manuscript deals with the recent advancements, the future prospects, and open issues of the Electro sinter forging (ESF) process. The author reports several examples regarding the use of ESF to prepare different materials (metals and alloys). I recommend the publication of this manuscript to be published in Metals with some changes listed below:
#1 In general, it is difficult to distinguish which results are the new results for this paper and which are the results from the previous studies. For the former case the author needs to give much more details of the sintering parameters and testing details, like, the energy used, the pressure, any die/punch were used…for example, the process parameters of the eForged 100Cr with near-net shape, the impact test details of stainless steels.
Answer: Thank you for the considerations. I have added the sintering parameters on the near net shape 100 Cr6. I have also added a table with an extensive review of the processing parameters and the references. I would like to have measured impact test results but unfortunately we are still not equipped for that and/or have found no one that has helped in measuring the impact strength of the parts. We are actively working on this to have measured data.
#2 the sectioning of the manuscript is confusing. For example, the Iron based and 100. Cr6-like composition are below metals, but tool steel/stainless steel are a new sections, parallel to metalsand copper based. Please rearrange it.
Answer: It was arranged properly in the original submission and changed during the formatting for the magazine. Should be ok now in the revised version.
#3 there are a lot of failed cross-references, please check.
Answer: the original version didn’t have any issue, the problem should be fixed now, it was the images.
#4 it is maybe better to put both of the curves in Fig5, for better comparison.
Answer: Yes, second curve added. Thank you.
#5 the author states that avoiding “old” oxidized powders is critical to achieve good sintering quality. I think this is a common issue for powder metallurgy in general. Is there any specificity for ESF?
Answer: we are working on the topic and investigating the shelf life of powder as well as the behavior of “as received” powders from powder producers. As no de-oxidizing atmosphere is possible we have found workarounds which are effective to produce tough parts but that do not remove the oxides, rather they move them around and create new surfaces (such as rapidly ball milling the powders before consolidation).
#6 please give a specific description of Fig7 in the caption. What are the three figures? and add also a scale.
Answer: the images have been reduced to two, larger, so the scale is visible and a description has been added.
Answer: Yes, thank you, done!
Round 2
Reviewer 1 Report
It is quite difficult to evaluate the manuscript in its current form. There are too many issues with the formatting, font sizes, legibility and the preparation of the figures. The work still requires a careful major revision:
-Most of the figures are in low resolution. The scale bars are not legible. Figure 8 is far too blight
- Figure 6, A axes are underlined in red, B I cannot read the Y axis
- Pressures in the order of few hundreds MPa are sufficient to achieve some densification even without application of an electrical discharge, refer to the work by Gutmanas et al. https://doi.org/10.1016/0036-9748(79)90380-6. Reference values for cold pressed samples should be added in table 1.
Author Response
Please see attachment.
Author Response File: Author Response.pdf
Round 3
Reviewer 1 Report
There are still several issues with the work for example Bismuth telluride is Bi2Te3 not BiTe.
Author Response
Thank you. Another through reading has been done and minor revisions have been made.
Bismuth Telluride has been corrected and BiTe has been substituted with Bi2Te3. NdFeB has been replaced throughout all the article with Nd2Fe14B.
