Mechanical Behaviour and Failure Mode of High Interstitially Alloyed Austenite under Combined Compression and Cyclic Torsion
Round 1
Reviewer 1 Report
The investigations on the hardening / softening behavior and crack formation and propagation of a material under static pressure and cyclic torsion were introduced in the manuscript. Some interesting phenomena closely related to multiaxial non proportional loading observed in experiments are analyzed. These studies are of great significance. However, there are some obvious issues, which affects the readability of the paper. The following insufficiencies have to be improved before publication:
- There is no enough description of material information, such as chemical composition and mechanical properties of the test material.
- There is no metallographic diagram, which should have been exhibited in Section 2.2.
- How to measure the axial strain and torsional strain (or torsional angle) of the specimen? The applied extensometer and the gauge length are not mentioned. These should have been introduced in the paper.
- After loading, the material enters the plastic state, and the stress and strain on cross-section of the sample are non-linear and non-uniform. The manuscript should mention how to calculate the shear stress distribution of the sample according to the tested torque.
- Is the boundary condition setting of finite element calculation consistent with the measured measuring point setting? This should be explained.
- The constitutive model and corresponding material parameters used in the finite element calculation are lack of introduction.
- "Table 1" in line 162 should be "Table 2".
- "Maximum shear stress at beginning of experiment" and "calculated von Mises stress… at the end of each experiment" in Table 2 is lacking of the calculation basis.
- Labels (a), (b), (c), (d), (e), (f) and (g) are not seen in Figure 5.
- Why "the experiment with 5 ° was stopped before cracks formed"? This should be explained.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The subject of the paper is interesting and important, the behaviour of different structures or structural element under multiaxial loads, especially under fatigue loads, are in the centre of attention. The approaches of the research and the applied methods are up-to-date. Unfortunately, the presentation of the research work and the results is overall not unambiguous, partially redundant and wordy, significant elements and details have not been described. Consequently, the manuscript should be amended and abridged consistently.
Please,
- formulate the direct aims of the manuscript e.g. in the end of the section 1 (Introduction);
- add the chemical composition and the most important mechanical properties of the investigated material;
- consider the increase of the absolute sizes of the light microscopy images in Figures 8, 9 and 10, along with consider the applicability of same magnifications in the figures.
Under the references, publications belonging to wide variety of materials (e.g. “welded joints”, “Ti-6Al-4V”, “composites”, “AZ61A magnesium alloy”, “pure copper”) can be found. Are the results and considerations in these publications really relevant and comparable from point of view your research?
Please
- consider the unification of the used forms of the references in the text (name of authors vs. number of references in brackets);
- correct the typing errors belonging to Table 2, because Table 2 has been referred as Table 1 (in more cases);
- add the symbol of the shear stress in row 148.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The article contains many interesting observations and research, especially in multi-axis loading. The manuscript's strengths are the perfectly described research methodology and the substantive discussion of the research results based on numerous references to the literature.
The article has the correct structure, and the cited literature contains references to a broad time frame. The executive summary provides essential information and is of appropriate length. The introduction is well prepared based on properly selected literature and well introduced to the analyzed area of research.
The description of the methods is factual and comprehensible. The chapter results and discussion contain references to clear illustrations. It's worth stressing that the authors made rarely seen fatigue tests conducted under different cyclic torsional angles, with superimposed axial static compression loads. All test results are clearly described and contain numerous references to the drawings included in the work. The illustrations presented in this chapter are well specified and deliver an appropriate editorial level. The conclusions presented in the paper contain the most critical observations obtained from the conducted research.
One note: Please consider the possibility of the scale unification in Figure 5 for strains as done for stresses.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The author made a serious reply to the comments of the reviewer and made appropriate modifications to the original text.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
Thanks the Authors for the valuable amendments, the added information and the corrections of more details; the modifications were highlighted in the manuscript (non-published version) and were explained in the authors cover letter file.
The direct content, in indirect mode the aims of the manuscript have been formulated in the section 1.
The chemical composition and the most important mechanical properties of the investigated material have been added at the beginning of the subsection 2.1; unfortunately, nominal values have been added.
I can accept the Authors’ answer belonging to the absolute sizes of the light microscopy images.
I can accept the Authors’ answer related to investigated materials in the referred publications, too. On the one hand, a few sources have been changed; on the other hand, the justifications were convincing.
I have written in my first review report: “Please, consider the unification of the used forms of the references in the text (name of authors vs. number of references in brackets.” In my opinion, it is preferable using the same type of the references in the text part of a manuscript. Authors have been used four types:
- name of the author(s) and farther the number of reference in square brackets (e.g. “Fatemi and Socie observed that the shear stress on the critical plane often leads to initial cracks and normal stress promotes crack propagation [8].”, rows 45-47);
- text and number of reference in square brackets (e.g. “Furthermore, previous research [12] has shown …”, rows 50-51);
- name of the author partially italics and the number of reference in square brackets directly after (e.g. Mocˇilnik et al. [13] …”, row 55);
- name of the author without italics and the number of reference in square brackets directly after (e.g. “As was observed by Kang et al. [19], …”, row 302).
Please, consider my suggestion.
The typing errors have been corrected.
Author Response
Please see attached file
Author Response File: Author Response.pdf
