Dynamic Recrystallization and Hot-Working Characteristics of Ni-Based Alloy with Different Tungsten Content
Round 1
Reviewer 1 Report
The ideas formulated in introduction are not well structured in a logical succession.
“ the new alloy was referred to as GY200” ? with two variants: 2W and 4W!
“The stress curves of the alloy corresponding to deformation at 1000 °C and 0.01 s-1 (2W) and at 1000 °C and 0.1 s-1 (2W) fluctuated significantly “; .....and at 1000 °C and 0.1 s-1 (4W) is corect !
“A previous study showed that DRX occurred more easily at higher strain rates and lower deformation temperatures (than at lower rates and higher temperatures) “ .... “The DRX process could be activated at a relatively high deformation strain rate and deformation temperature” Explain the above affirmations in connection with the comments in the article, see below:
The authors say, at pct.2.3: “fully DRX grains could be obtained by increasing the deformation temperatures to 1150”; “Full DRX grains are achieved when deformed at 1200 °C, but micro-cracks could be seen around grain boundaries”!!!
How was exactly the constant α obtained? The graphs concerning this calculus are absent. And also the stress exponent, n?
Fig 6 caption: έ !
Why the TEM analysis was performed only on the 2 W alloy? Also data for the misorientation distribution! How were obtained data for Fig. 10 b and Fig.11?
Figure 9 appears twice! “Figure 9. The misorientation distribution maps of 2W deformed at 1050-1150 °C with a strain rate of 219 1s-1; (a)1000 °C; (b)1050 °C; (c)1100 °C; (d)1150 °C.”
“Table 2. The frequency of misorentation angle at different deformed temperature.’” Must be completed : for the 2W alloy.
At which alloy refer Fig .12 and Fig. 13? Which is the difference between Fig.12c and Fig.12e? s-1 is correct in Fig. 12!
Some details concerning the algorithms and/or softs used to obtain Fig. 14 and Fig. 15. Eq. 5-7 are just generic ones. The comments are based on Fig. 14 and Fig. 15.
For many passages the English language is poor. All text must be checked.
Author Response
Metals- 444609-reply
Dynamic Recrystallization and Hot Working Characteristics of Ni-based Alloy with Different Tungsten Content
Dear Reviewer,
I am writing to reply your mail on February 18, 2019.
First of all, my thanks go to reviewer for their comments on the manuscript " Dynamic Recrystallization and Hot Working Characteristics of Ni-based Alloy with Different Tungsten Content" (Full Paper, No. 444609). The comments from Reviewer are highly sincere and I have revised the paper in accordance with the suggestions.
My answers to your comments are written in the Word file.
Thank you very much.
Sincerely yours,
Zhi-hua GONG
February 18, 2019
No.1-1:The ideas formulated in introduction are not well structured in a logical succession.
Thank you very much for the suggestion. The introduction has revised and marked in red. The line 33-51 are replaced by “Owing to their high melting points, W and Mo are commonly occurring elements in Ni-based alloys. W has a larger atomic radius than Mo and, hence, may result in greater matrix lattice expansion and higher yield strength of the alloy[10,11]. In the present work, tungsten (W) was used to replace partial Mo with the aim of obtaining excellent creep rupture strength of the Waspaloy Ni-based alloy to acquire a new alloy which was referred to as GY200[12,13]. However the hot workability of the new alloys is affected to some extent when superabundant W is added. In order to explain the mechanisms of hot deformation and correlate the flow stress and microstructure evolution, hot deformation constitutive equations were invented to describe the hot deformation behaviors of the GY200 super alloys. Constitutive equations of the alloys with different W content are established based on the stress-strain curves obtained by compression at different temperatures and deformation rates. The hot deformation of super alloys is very complex including work hardening (WH), dynamic recovery (DRV) and dynamic recrystallization (DRX)[14]. The effect of W addition on WH, DRV and DRX is studied by analysing the microstructure evolution in this paper. Moreover, the hot working maps, which are based on the dynamic materials model (DMM), have proven an excellent response of the processing optimization and an excellent tool for monitoring the microstructural evolution of a material. The optimum thermal deformation parameters are worked out based on the hot working maps and the microstructure.”
No.1-2 “ the new alloy was referred to as GY200” ? with two variants: 2W and 4W!
The GY200 Ni-based alloy is a patent product designed by our research group and is the name of a series alloys with different W and Mo content, in the alloy, W content from 0 to 8%, Mo content from 0 to 3.5%. In this paper, only two alloys, 2%Mo2%W and 2%M04%W, are prepared to investigate the influence of W content on the hot deformation behavior, dynamic recrystallization and hot workability.
No.1-3: “The stress curves of the alloy corresponding to deformation at 1000 °C and 0.01 s-1 (2W) and at 1000 °C and 0.1 s-1 (2W) fluctuated significantly “; .....and at 1000 °C and 0.1 s-1 (4W) is corect !
The content of “and at 1000 °C and 0.1 s-1 (4W) is corect” has been added to manuscript.
No.1-4: “A previous study showed that DRX occurred more easily at higher strain rates and lower deformation temperatures (than at lower rates and higher temperatures) “ .... “The DRX process could be activated at a relatively high deformation strain rate and deformation temperature” Explain the above affirmations in connection with the comments in the article, see below:
The authors say, at pct.2.3: “fully DRX grains could be obtained by increasing the deformation temperatures to 1150”; “Full DRX grains are achieved when deformed at 1200 °C, but micro-cracks could be seen around grain boundaries”!!!
This question is very important to me, the comments of “fully DRX grains could be obtained by increasing the deformation temperatures to 1150” and “Full DRX grains are achieved when deformed at 1200 °C” are all derived from the microstructure evolution and DRX analysis(THE EBSD analysis of DRX fraction) after deforming at different deformation temperature. The explanation of “but micro-cracks could be seen around grain boundaries” is derived from the TEM images observation(Fig.9(g) of original manuscript), the authors consider that it is a micro-crack in GB in figure 9(g) is mainly derived from the grain boundary melting which has been shown in Fig.13(original manuscript). But another reviewer has given different opinion as follow: “Line 173-14: regarding the interpretation of Fig.9g, these cracks are not seen in GBs, as can be noticed by the small changes in the band contours which indicate a small angular deviation, i.e., small changes in the crystallographic orientation.”, the authors have discussed with some professional and given a conclusion that the micro-cracks can’t be affirmed, meanwhile, this image does not contribute to the conclusion of the paper, hence we deleted the image in the revised manuscript. I’m sorry that it was the author's negligence not considering them clearly.
No.1-5: How was exactly the constant α obtained? The graphs concerning this calculus are absent. And also the stress exponent, n?
We have added the content as following:
The α is a constant and can be defined by α=β / n′, at constant temperature, β and n′ can be expressed by equation (2) and (3), respectively. The detailed solutions refer to reference.
(2)
(3)
The value of the stress exponent, n, is then related to ln[sinh(ασp)] and ,and which can be obtained by equation (4)
(4)
No.1-6: Fig 6 caption: έ !
This mistake has been corrected.
No.1-7: Why the TEM analysis was performed only on the 2 W alloy? Also data for the misorientation distribution! How were obtained data for Fig. 10 b and Fig.11?
The TEM analysis has been used to describe the dynamic recrystallization nucleation and microstructure evolution during hot deformation, the authors thought that the two alloys with different W content have same dynamic recrystallization nucleation and growth mechanism, so we select one alloy as an example for analysis.
The data of Fig10 and Fig11(original manuscriot) were obtained from EBSD analysis data, we have finished the EBSD experiments for 2W and 4W in fact, but some compression experimental samples have lost for some reason(we only have the data of strain-stress curves), for example, the experiment samples of 4W deformed at 1000 ℃ were lost. So the authors choose 2W to analyse the misorientation distribution maps.
The data for the misorientation distribution was used to describe the recrystallization behavior during deformation, the sample of 4W deformed at 1000 ℃ and 1 s-1 was lost, and we could not compare systematic with 2W, so the data for misorientation distribution of 4W was not shown in original manuscript, but the author has added the misorientation distribution data of 4W into Table 2 in revised manuscript.
No.1-8: Figure 9 appears twice! “Figure 9. The misorientation distribution maps of 2W deformed at 1050-1150 °C with a strain rate of 219 1s-1; (a)1000 °C; (b)1050 °C; (c)1100 °C; (d)1150 °C.”
I’m sorry, that is my negligence, the mistake has been corrected.
No.1-9:“Table 2. The frequency of misorentation angle at different deformed temperature.’” Must be completed : for the 2W alloy.
Thank you very much, the table 2 has been revised and added the data of 4W in it.
No.1-10:At which alloy refer Fig .12 and Fig. 13? Which is the difference between Fig.12c and Fig.12e? s-1 is correct in Fig. 12!
Fig.12 an Fig.13 are all pictures of alloy 2W. Fig.12c and Fig.12e is the same sample, Fig.12c shown the compressed plane and Fig.12e shown the plane perpendicular to the compression direction. The authors have added the sample name to the manuscript.
“s-1” in Fig.12 has been corrected to “s-1”.
No.1-11:Some details concerning the algorithms and/or softs used to obtain Fig. 14 and Fig. 15. Eq. 5-7 are just generic ones. The comments are based on Fig. 14 and Fig. 15.
The parameter m can be obtained by the relationship between strain rate and stress, as the follow equation:
m=
The first step is solving m, then η and ξ are obtained at different strain rate and deformation temperature, power dissipation map presented in the form of isoefficiency 2D contour map can be obtained by plotting the η against temperature and strain rate. Then，according to Eq. (7) (original manuscript eqution number), instability is expected to occur when ξ becomes negative at a given deformation condition. Thus, processing map can be developed by superimposing the variation of the instability parameter ξ with temperature and strain rate on the power dissipation map at a certain strain.
The author considers that the steps of making hot working maps are universal and can be obtained by referring to some references, so the process is not described in detail.
No.1-12:For many passages the English language is poor. All text must be checked.
Thank you for your advice, the revised manuscript has been edited by MDPI for check the gramma mistake.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript describes the effects of W additive (2 and 4%) to a Ni-based alloy with the DRV and DRX mechanisms. This investigation was conducted via high temperature compression tests at different strain rates, collaborated with microstructural characterization employing OM, EBSD and TEM techniques.
There are many aspects in the manuscript that require deeper analysis and possibly some reconsideration. Therefore, I would reconsider the paper ‘Dynamic Recrystallization and Hot Working Characteristics of Ni-based Alloy with Different Tungsten Content’ for publication in Metals after major corrections. I would ask to include a detailed description of changes made in the manuscript including answers to my questions.
Line 54: Table 1 is confusing. It is interpreted as if the authors researched on 4 different alloys. Please try to describe each alloy using a single row.
Line 57: Fig.1 was taken using OM and not EBSD, it is not a crystallographic representation of that region, i.e., this is not OIM. Please correct.
Line 60: “some annealing twins”.. This observation is not valid. As the matrix is FCC, annealing twins have well-defined interfaces (semi and full coherency with the matrix) which are not noticed in Fig.1. Please mark positions of twins.
Line 65-66: Please add the description of the standard (ASTM..) used for testing.
Line 74-77: The authors did not describe how did they prepare samples for EBSD analysis. The authors should also describe how did they collect and analyzed EBSD data, including: SEM illumination conditions, definition of region of interest, step size, hit ratio, the number of phases included in the interpretation, cleaning rutine, the post-process packages used, boundary criteria.
Line 98-99: “In general, the peak stress of 2W was higher than that of 4W, owing to the higher W content”..?, Most experiments show a higher peak stress for the 4W, resultant of a stronger degree of solid solution strengthening mechanism. This is accounted to higher W content. Please revise or explain. Also, explain why the peak stress for 2W is higher in the case of 1s-1.
Section 2.3. (Line 137-160) - EBSD was not properly employed or analyzed. This entire section lacks a mandatory discussion on the nucleation and growth in terms of crystallographic texture including, texture modification as a function of testing temperature and strain rate. The authors should add a map showing the microstructure and pole-figure analysis of the micro-texture prior and post thermo-mechanical testing and explain the changes in terms of GBs alternation and activated slip systems.
Line 138: “High definition”. Did the authors point to the small ROI or to the small spot size used in the scanning protocol? Please explain or revise.
Line 138: Please describe sample axis and compression axis. Also, add to text - which IPF are we looking at.. this is mandatory to all OIM presentations in the manuscript.
Line 140 and caption of Fig.7. is it 1050 or 1000deg?? I am completely lost there.
Line 142: Volume fraction of recrystallized grains… What are the criteria
employed for differentiating grains? (critical angles? KAM/BC/GOS values? density of GBs? Size or morphology?)
Line 148: “recrystallized grains keep partial deformed features yet”… please explain.
Line 149: “consist of DRV and DRX…” again, the authors point to an observation without explaining their unique interpretation. Was it the intra-grain grain boundary density which was used for differentiating? was it the texture component related to the compression axis??? PLEASE EXPLAINE!
Line 153-154: Fig 7a and Fig 8a, for similar conditions, the 2W and the 4w show a completely different microstructure. This must be addressed in the manuscript. The authors did not consider it thoroughly - “Changes in the micrographs of two different W content alloys are consistent with the trends observed in the strain-stress curves”. Please elaborate.
Line 161: Dark filed TEM images… and not “pictures”. Please revise.
Fig. 9c: The authors should point to a clearer region which consist of dislocations. On the right to the “recrystallized grain”, a grain which consist of parallel dislocation network is presents. Please correct in that Fig.
Fig.9e – The visibility of slip band is not straightforward or not valid. As for the recrystallized grains.. I do not understand the approach employed by the authors.. they did not used (perhaps, not familiar to authors) the traditional visibility criteria such as b*g and therefore, pointing to a specific grain without considering diffraction conditions is meaningless and should be avoided as it does not represent the true state of the microstructure.
Fig.9f. r’ or gamma’ phase??? did the authors checked these particles using EDS measurements and/or SAD?? It looks like a contamination which is commonly added during TEM preparation, using ion milling… please comment on this.
Line 173-14: regarding the interpretation of Fig.9g, these cracks are not seen in GBs, as can be noticed by the small changes in the band contours which indicate a small angular deviation, i.e., small changes in the crystallographic orientation.
Line 177-179: this should be moved to the description of EBSD in the experimental section.
Line 191-225: Earlier in the manuscript, the authors described the microstructure using EBSD analysis. This was followed by the TEM characterization of “pseudo-nano” features such as GBs and dislocations. Now, the authors go back to EBSD… ?! not coherent and should be explained or revised.
Fig 9. Where are all those precipitates which were described in the introduction section? What is their contribution to the DRV.. this should be presented and not only theoretically described in the manuscript.
Line 189: The driving force for nucleation and growth is related to the difference of GBs characteristics and mobility of dislocations as a function of the micro-texture, i.e, activated slip system. The authors only described the simple concept of misorientation but neglected the idea of mobility. Please comment on that I the manuscript.
Fig 11. Authors present an analysis of the recrystallization fraction at a 1 s-1 rate, which present a higher peak stress for the 2W (not so obvious why). Following Fig.4, other experiments show a different behavior. I wonder why the authors present this particular analysis. I would expect an explanation in the manuscript. Additionally, the authors should correlate the peak stress to the DRV fraction. Please include in the manuscript.
Author Response
Metals- 444609-reply
Dynamic Recrystallization and Hot Working Characteristics of Ni-based Alloy with Different Tungsten Content
Dear Reviewer,
I am writing to reply your mail on February 18, 2019.
First of all, my thanks go to reviewer for their comments on the manuscript " Dynamic Recrystallization and Hot Working Characteristics of Ni-based Alloy with Different Tungsten Content" (Full Paper, No. 444609). The comments from Reviewer are highly sincere and I have revised the paper in accordance with the suggestions.
My answers to your comments are written in the Word file.
Thank you very much.
Sincerely yours,
Zhi-hua GONG
February 18, 2019
Metals- 444609-reply
Dynamic Recrystallization and Hot Working Characteristics of Ni-based Alloy with Different Tungsten Content
2-1#:Line 54: Table 1 is confusing. It is interpreted as if the authors researched on 4 different alloys. Please try to describe each alloy using a single row..
Thank you for your suggestion, the table 1 has been revised.
2-2#:Line 57: Fig.1 was taken using OM and not EBSD, it is not a crystallographic representation of that region, i.e., this is not OIM. Please correct.
Thank you, it is my lack of the knowledge of EBSD, this mistake has been corrected in the revised manuscript.
2-3#:Line 60: “some annealing twins”.. This observation is not valid. As the matrix is FCC, annealing twins have well-defined interfaces (semi and full coherency with the matrix) which are not noticed in Fig.1. Please mark positions of twins.
You are right. These pictures can’t show us the annealing twins clearly, so we have renewed the OM images which are suitable for observing the twins.
2-4#:Line 65-66: Please add the description of the standard (ASTM..) used for testing.
We have added the content of “The standard of ASTM E209-2000(2010) was used for testing.” to the manuscript.
2-5#:Line 74-77: The authors did not describe how did they prepare samples for EBSD analysis. The authors should also describe how did they collect and analyzed EBSD data, including: SEM illumination conditions, definition of region of interest, step size, hit ratio, the number of phases included in the interpretation, cleaning rutine, the post-process packages used, boundary criteria..
Thank you for your suggestion, this problem has been resolved by adding some relevant content to the article.
2-6#: Line 98-99: “In general, the peak stress of 2W was higher than that of 4W, owing to the higher W content”..?, Most experiments show a higher peak stress for the 4W, resultant of a stronger degree of solid solution strengthening mechanism. This is accounted to higher W content. Please revise or explain. Also, explain why the peak stress for 2W is higher in the case of 1s-1.
I’m sorry that it’s my negligence led to this mistake, the right content is” In general, the peak stress of 4W was higher than that of 2W, owing to the higher W content, which increased the solid solution strengthening effect and the deformation resistance.”
The question of “the peak stress for 2W is higher in the case of 1s-1” is difficult to explain. From the experimental data, it could be found that the peak stresses for 2W at 1000℃with 1s-1 and 1050℃with 0.1s-1 are higher than that of 4W. We have added the content of “The probable reason for this is that the GY200 Ni-based alloys contain some strengthening phases such as TiC, M23C6 and γ′ phases[20]; these precipitated phases could not resolve completely during heating before hot compression, and thus the peak stress decreases due to the reduction of soluble atoms that hindered dislocation movement. Moreover, the non-uniform microstructure and different lubrication in experiments would affect the peak stress as well.” to the manuscript to explain it.
2-7#:Section 2.3. (Line 137-160) - EBSD was not properly employed or analyzed. This entire section lacks a mandatory discussion on the nucleation and growth in terms of crystallographic texture including, texture modification as a function of testing temperature and strain rate. The authors should add a map showing the microstructure and pole-figure analysis of the micro-texture prior and post thermo-mechanical testing and explain the changes in terms of GBs alternation and activated slip systems.
It’s a very important suggestion to me, the EBSD was not properly employed in this section, the IPF maps could not be used to analyze the DRV and DRX in hot deformation. We have replaced the IPF maps with band contrast maps which can show the structure of DRX and deformed grains clearly. The content of this section are renewed fully. Meanwhile author did not reply the question of “The authors should add a map showing the microstructure and pole-figure analysis of the micro-texture prior and post thermo-mechanical testing and explain the changes in terms of GBs alternation and activated slip systems.”; the reason was the purpose of this section is to describe the microstructure evolution of DRX and deformation bands, and explain the influence of W content on the evolution of microstructure. I have not enough data to explain the changes in terms of GBs alternation and activated slip systems, we can study this question in the future.
There are some questions about this manuscript I must explain to the reviewer, the author has used improper theoretical and experimental methods to characterize DRV and DRX, so in the revised manuscript, the content about EBSD, DRV and DRX are reedited on the basis of extensive reading the relevant literature, I apologize for causing additional job to the reviewer.
2-8#: Line 138: “High definition”. Did the authors point to the small ROI or to the small spot size used in the scanning protocol? Please explain or revise. Line 138: Please describe sample axis and compression axis. Also, add to text - which IPF are we looking at.. this is mandatory to all OIM presentations in the manuscript.
The content of “High definition” has been deleted, the deformation axis and direction have added to the maps and the content of “which band contrast maps are we looking at is vertical to compression direction, this is mandatory to all EBSD maps presentations in the manuscript.” has added to the revised manuscript.
2-9#:Line 140 and caption of Fig.7. is it 1050 or 1000deg?? I am completely lost there..
Fig.7 is the maps of 2W which deformed at 1000, 1050, 1100 and 1150 °C, Fig.8 is the maps of 4W which deformed at 1050, 1100, 1150 and 1200 °C, the deformation temperature of 2W and 4W is different, because the samples of 4W deformed at 1000 °C have lost for some reason and we only have the data of stress-strain curves of them.
2-10#: Line 142: Volume fraction of recrystallized grains… What are the criteria employed for differentiating grains? (critical angles? KAM/BC/GOS values? density of GBs? Size or morphology?)
The data of volume fraction of recrystallized grains is obtained from EBSD analysis and the criteria employed for differentiating grains is GOS values, the content has added to revised manuscript.
2-11#: Line 148: “recrystallized grains keep partial deformed features yet”… please explain.
This comment is not rigorous and correct, which has been removed.
2-12#:Line 149: “consist of DRV and DRX…” again, the authors point to an observation without explaining their unique interpretation. Was it the intra-grain grain boundary density which was used for differentiating? was it the texture component related to the compression axis??? PLEASE EXPLAINE!
I’m sorry that I have used the IPF maps not properly in this section and given misleading description, DRV can’t be observed by IPF maps, I have renewed the content of this section. The question “2-7#” and “2-12#” are all about the DRX and DRV, the IPF maps are not used correctly here.
2-13#：Line 153-154: Fig 7a and Fig 8a, for similar conditions, the 2W and the 4w show a completely different microstructure. This must be addressed in the manuscript. The authors did not consider it thoroughly - “Changes in the micrographs of two different W content alloys are consistent with the trends observed in the strain-stress curves”. Please elaborate.
Fig 7a is 2W deformed at 1000 ℃ and 1S-1, Fig 8a is 4W deformed at 1050 ℃ and 1S-1, they are not similar deformation condition, Fig 7b and Fig 8a are similar conditions. We have lost the compression experimental samples of 4W deformed at 1000 ℃ for some reason, so the EBSD data of 4W deformed at 1000 ℃ is missing.
“Changes in the micrographs of two different W content alloys are consistent with the trends observed in the strain-stress curves”, the authors means that the DRX could be obtained at deformed temperature of 1000 to 1150 ℃ and strain rates of 0.01 to 10 S-1, because peak stress occurred on the strain-stress curves, that mean DRX has happened, we can draw the same conclusion from microstructure observation. I have replace this content with “Compare the microstructures of Figure 7 and 8, it can be found that, DRX can be observed at different deformation temperatures, which are consistent with the trends observed in the strain-stress curves (see Fig. 2 and Fig. 3).”, do you think this modification is appropriate?
2-14#:Line 161: Dark filed TEM images… and not “pictures”. Please revise. Fig. 9c: The authors should point to a clearer region which consist of dislocations. On the right to the “recrystallized grain”, a grain which consist of parallel dislocation network is presents. Please correct in that Fig. Fig.9e – The visibility of slip band is not straightforward or not valid. As for the recrystallized grains.. I do not understand the approach employed by the authors.. they did not used (perhaps, not familiar to authors) the traditional visibility criteria such as b*g and therefore, pointing to a specific grain without considering diffraction conditions is meaningless and should be avoided as it does not represent the true state of the microstructure.
Thank you for your suggestion, Line 161 has been revised and the content of images description has been reedited. The “slip band” was not correctly used here and has been replaced by “deformed bands”.
The TEM was used to observe the DRX, DRV, dislocation and deformed bands. The authors thought that the recrystallized grains have characteristic of equiaxed and lower dislocation, and The DRV accompanied by dislocation movement and reorganization, which could be identified in dark field TEM images. Hence the TEM has been used to describe the DRX and DRV during hot deformation.
We have deleted some TEM images, which were considered have no effect on the conclusion of the manuscript, the deleted images related to the question of “2-15#” and “2-16#”.
2-15#：Fig.9f. r’ or gamma’ phase??? did the authors checked these particles using EDS measurements and/or SAD?? It looks like a contamination which is commonly added during TEM preparation, using ion milling… please comment on this.
We can confirm that the particle is gamma prime phase, and we have found it in different samples have shown as following images (these samples are not prepared for hot deformation). The authors shown the images of r’ phase in the paper was because r’ was difficult to find and most of them have dissolved into matrix, but we did not found its contribution to the DRX, so we have deleted the image of it in the renewed manuscript because it has no influence on the conclusion.
2-16#：Line 173-14: regarding the interpretation of Fig.9g, these cracks are not seen in GBs, as can be noticed by the small changes in the band contours which indicate a small angular deviation, i.e., small changes in the crystallographic orientation.
The authors have discussed with some professional and given a conclusion that the micro-cracks could not be affirmed by this image, and this image did not influence on the conclusion of the manuscript, hence, we deleted the image in the revised manuscript. I’m sorry that it was the author's negligence and not considering them clearly.
2-17#：Line 177-179: this should be moved to the description of EBSD in the experimental section.
Lin177-179 has been moved to section 1.
2-18#：Line 191-225: Earlier in the manuscript, the authors described the microstructure using EBSD analysis. This was followed by the TEM characterization of “pseudo-nano” features such as GBs and dislocations. Now, the authors go back to EBSD… ?! not coherent and should be explained or revised. Fig 9. Where are all those precipitates which were described in the introduction section? What is their contribution to the DRV.. this should be presented and not only theoretically described in the manuscript.
Thank you for your suggestion, the structure of section 2.3 is confused, so the authors have changed the structure of this part following the reviewer’s advice, we have moved the part of TEM to the end of this section. From dark filed TEM images, we have found some precipitations in the grain, the precipitation (not r’ phase, it is a TiC particle) in image (a) hinders GB movement, and the precipitations (not r’ phase) in image (b) hinders dislocation movement, that means the DRX and DRV have been hindered by precipitation. The authors have added image (a) and the content of “Fig.13 (d) shows a precipitation appears near the grain boundary resulting grain bending, and the movement of GB is hindered by precipitation, meaning that the DRX can be restrained precipitated phases.” to the manuscript
(a) (b)
2-19#：Line 189: The driving force for nucleation and growth is related to the difference of GBs characteristics and mobility of dislocations as a function of the micro-texture, i.e, activated slip system. The authors only described the simple concept of misorientation but neglected the idea of mobility. Please comment on that in the manuscript.
We have added a detailed explain about the nucleation and growth of DRX to the manuscript, the content as following:
DRX is intensely dependent on deformation degree, strain rate and temperature during hot deformation[14]; the recrystallization nuclei initially form in a local region (deformation band, grain boundary and near inclusion) with a high deformation degree. Two classical dynamic recrystallization nucleation theories, the DBs bulging mechanism and sub-grains rotation mechanism, are widely accepted by scholars[27,28]. The frequencies of LAGBs with θ in the range of 0-5° have larger value when deformed at 1000 °C of 2W and 1050°C of 4W, the probable reason is some deformed grains with lot of deformaed bands and sub-grains, which are dominated by LAGBs, are retained in the microstructure( see Fig.7a and 8a and 13) . The sub-grains with LAGB have lower GB migration rate, and thus two adjacent sub-grains with low misorientation merge to form a new DRX grain with large misorientation by rotation; the public sub-GB disappearing and new GB forming during the grain merging are all executed by dislocations slipping and climbing. The frequency of HAGBs increased with increasing deformation temperature, the mainly reason is that the rate of atom diffusion and dislocation movement accelerated with increasing deformation temperatures, which resulting the DRX grain growth and misorientation increase. For higher W content, the amount of W atoms in 4W is more than that of 2W, hence, atoms diffusion and dislocations movement in 4W are more difficult, resulting in the HAGBs frequncy of 4W is lower than that of 2W.”
2-20#:Fig 11. Authors present an analysis of the recrystallization fraction at a 1 s-1 rate, which present a higher peak stress for the 2W (not so obvious why). Following Fig.4, other experiments show a different behavior. I wonder why the authors present this particular analysis. I would expect an explanation in the manuscript. Additionally, the authors should correlate the peak stress to the DRV fraction. Please include in the manuscript.
I’m sorry that I have given a misconception to the reviewer that I want to explain the reason of “why 2W has a higher peak stress than 4W at 1050 °C with 1 s-1”. Fig.11 is the proportion of recrystallization of two alloys deformed at 1000-1200 °C and 1s-1, the purpose of author’s display this figure is to explain the relationship between DRX, DRV and Sub-DRX with different W content alloys, which can provide evidence that the DRV is difficult when the alloy with higher W content. Fig11 can’t explain the problem of “why 2W has a higher peak stress than 4W at 1050 °C with 1 s-1”, as the reply of 2-6#, the reason of “why 2W has a higher peak stress than 4W at 1050 °C with 1 s-1” has been given.
The authors have added a figure (Fig.12) to the manuscript to correlate the peak stress to the DRV fraction. The content as following:
“Fig.12 shows the correlation between the peak stress and DRV fraction of 2W and 4W after deformed at 1050, 1100 and 1150 °C at a strain rate of 1s-1. The alloy with a higher peak stress has a higher DRV frequency at similar deformation conditions; although the peak stress of 2W is higher than that of 4W at 1050 °C has been considered as an abnormal phenomenon. ”
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have reviewed the manuscript according with the comments made at Revision 1.
The corrections were included in the revised manuscript.
Reviewer 2 Report
To the authors, I accept the manuscript for publication in the current form but would kindly ask that future research will be carried out with more scientific soundness and control…..
