Influence of Deep Cryogenic Treatment on Microstructure and Properties of 7A99 Ultra-High Strength Aluminum Alloy
Round 1
Reviewer 1 Report
The authors addressed sufficiently the review comments. Therefore, the manuscript is recommended for publication.
Author Response
Dear reviewer and editor:
We are truly grateful to your critical comments and thoughtful suggestions about our paper submitted to Metals (Manuscript Number: metals-506600. Based on these comments and suggestions, we have made careful modifications on the original manuscript. All changes made to the text are in red color. Below you will find our point-by-point responses to the comments:
Comment 1:
(1) p.1, line 4-5 from below: change to …. due to the relatively high content of Cu
i.e. remove ‘element’
Response to Comment 1:
We have removed ‘element’ according to your request as shown in Page 1.
Comment 2:
(2) p. 3 Tensile properties: Why ‘6-MPa’ and ‘19-MPA’? Should be written 6 MPa and 19 MPa!
Response to Comment 2:
The ‘6-MPa’ and ‘19-MPA’ have been replaced by 6 MPa and 19 MPa in the manuscript.
Comment 3:
(3) p. 3 Therefore, the application of three deep cryogenic treatments can simultaneously enhance the tensile strength, …….should be ‘the deep cryogenic treatment
Response to Comment 3:
Thanks for the careful reviewer. In the manuscript, ‘the three deep cryogenic treatment’ has been replaced by ‘the deep cryogenic treatment’ in Page 3.
Comment 4:
p. 4 ….the dark field diffraction pattern - not meaningful phrasing/nothing like a dark field diffraction pattern! Should either be ‘the diffraction pattern’ ……. or ‘the dark field image’
Response to Comment 4:
In the manuscript, we have replaced ‘the dark field diffraction pattern’ by the SAED pattern. The SAED refers to the abbreviation of “selected area electron diffraction”. Please refer to the manuscript in Page 4.
Comment 5:
p. 4 ……that the precipitation is mainly η'-MgZn2 formed along the direction of the<011>crystal axis.
What do the authors mean by this statement and what is the basis for it? The authors need to clarify what they mean!
And what is the meaning of<011>in the figure caption of Fig.3?
The inset diffraction patterns in a Fig. 3a and 3b indicates that the images are obtained in the<001>-zone axis (of the Al-matrix)? With the 200 and 020 diffraction spots in the image plane, the normal is<001>and not<011>!
Response to Comment 5:
We are sorry for our mistake that the incidence direction of the diffraction spot should be along [011] zone axis. Meanwhile, we had made the wrong statement that the precipitation is mainly η'-MgZn2 formed along the direction of the<011>crystal axis. In the manuscript, the description has been corrected as “the SAED pattern indicates that the precipitation is mainly η'-MgZn2 (zone axis is [0 1 1]).” which has been marked in red in Page 4 and Figure 3.
Comment 6
p. 5 (section below Fig.4) below I doubt it is meaningful/realistic to give the volume fractions of Zn, Mg, Cu clusters with an accuracy of three decimals?
Response to Comment 6:
In the experimental, the volume fractions of the atom clusters with different sizes were calculated through 3DAP device acquisition. We have changed the accuracy of volume fraction from three decimals to two decimals to insure the accuracy. Please refer to the manuscript in Page 5.
We have tried our best to improve the manuscript and made some changes in the revised manuscript. These changes will not influence the content and framework of the paper. We appreciate for the editor and reviewers’ warm work earnestly, and hope that the corrections will meet with approval. Once again, thank you very much for your comments and so much good advises.
Thank you and best regards!
My addresses are as follows:
Dr. Wenlin Gao
Key Lab of Electromagnetic Processing of Materials, Ministry of Education,
Northeastern University, Shenyang, Liaoning, 110004, China
E-mail: [email protected].
Reviewer 2 Report
The authors have been improved the paper following the reviewer's comments and suggestions.
Author Response
Dear reviewer:
Thank you for your efficient work and helpful comments in processing our manuscript entitled “Influence of Deep Cryogenic Treatment on Microstructure and Properties of 7A99 Ultra-High Strength Aluminum Alloy” We are very thankful for your constructive comments. We had studied the comments carefully in the manuscript which we hope meet with approval.
Once again, thank you very much for your comments and so much good advises.
Thank you and best regards!
My addresses are as follows:
Dr. Wenlin Gao
Key Lab of Electromagnetic Processing of Materials, Ministry of Education,
Northeastern University, Shenyang, Liaoning, 110004, China
E-mail: [email protected].
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The manuscript deals with an interesting subject but the number of experiments and the scientific explanation must be improved. The experimental work is based on two conditions, one is T6 and the second is T6-DCT and mechanical properties are related only to this two cases, owing to obvious conclusions. I would suggest a larger statistical work by comprising aging curves, even at different temperatures. English improvement would be appreciated. I would not reccommend the publication of the paper in its present form.
Author Response
In this paper, only a preliminary exploratory study on DCT as a new treatment process is carried out. Following the reviewer's suggestions, DCT will be further studied in our future work.
Reviewer 2 Report
The paper concerns the influence of the combined aging and deep cryogenic treatment of an extruded 7A99 Al-Zn-Mg-Cu-Zr alloy. The study employs mainly the use of EBSD, TEM, 3DAP and tensile testing for the investigation of microstructure and mechanical properties. The subject is relevant to the Journal scope and it is clearly written. Suggested revisions are following to be considered, in order to be further improved and accepted for publication:
1. In the experimental part (sec. 2), the description of thermal cycle is not well understood, as it is depicted also in Figure 1. Solution treatment temperature and duration are not explicitly presented. The analytical presentation, through a Table, of every thermal step followed, pertaining to T6 and T6-DCP processes will be helpful (temperature and duration/holding are required).
2. In Table 1, where the chemical composition of the alloy is reported, Ti and Be contents should be specified as maximum limits or within a certain range.
3. In sec. 2, more details concerning tensile testing procedure should be written; e.g. standard, equipment and specimen number, geometry and orientation. In general, experimental part is brief and it should be enriched.
4. The presentation of mechanical properties, as they have been acquired by the tensile testing and illustrated in Figure 2, is suggested to be done also using an appropriate Table, showing differences and percent variation between the examined thermal cycles, T6 vs T6-DCP.
5. The inserts of sub-figures’ symbols in Figures 3-6 are not well placed and are un-clear and also hide unnecessarily parts of images or graphs (especially in 6).
6. Scales in Figure 4, presenting TEM micrographs are not well discerned.
7. The language is almost sufficient, but additional proof-reading is necessary to eliminate minor grammar and editorial errors. For instance:
- L36: comprehensive (compressive?)
- L40: high strength stress (high strength stress)
- L83 (Table 2): e (?)
- L84: Mold (Liner?), Squeezing ratio (Extrusion ratio)
- L99-100: needs rephrase
- L108: microstructure (Microstructure)
In general, the units of physical entities have to maintain one single space from their numerical values: e.g. 705MPa (705 MPa)
Author Response
Please see the attached file.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
The paper is interesting. In the reviewer’s opinion, the authors need to improve the paper enlarging diverse sections as suggested below:
· First of all, the English needs to be improved.
· The acronyms should be defined before their utilization in the whole paper comprising the abstract.
· Keywords: the keywords should be reported in extended form not as acronyms.
· Table 2: the note after Table 2 should be inserted in the Table caption.
· Section 2: this section needs to be enlarged. This section should be included images of the utilized samples.
· Section 3. the experimental results are described using the figures but information on the utilized devices and parameters are not described.
· Subsection 3.1. This sub-section needs to be enlarged. The authors should be described the parameters utilized to obtain the tensile proprieties.
· Figure 3, 4, and 5 should be improved. For example: the letters a, b and the scale are not readable.
· Figure 5 is discussed but information regarding the 3DAP technology are missing.
· In Figure 6, the proportion of atom clusters of Zn, Mg, Cu elements is discussed, but also in this case information regarding the utilized technology are missing.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors did not try to improve the paper according to reviewer's suggestions. The manuscript is not sound for publication in its present form.
Author Response
1. I have revised the English expression of the manuscript.
2. The purpose of this paper is only to show that, DCT can accelerate the precipitation processing, refine precipitates and make the precipitates distribute uniformly, and improve the strength and plasticity of 7A99 aluminum alloy. I think the experiment and result can support this. The reviewer’s suggestion is very helpful, we will do more work following the suggestion.
Reviewer 3 Report
The authors have been improved the paper following the reviewer's comments and suggestions.
Author Response
Thank you so much!
