Hall-Petch Strengthening by Grain Boundaries and Annealing Twin Boundaries in Non-Equiatomic Ni2FeCr Medium-Entropy Alloy
Round 1
Reviewer 1 Report
The manuscript is well-written, the information is clear presented. The present manuscript can be considered for publication after minor changes.
1) General remark related for equations font: please use the same font/ size for all your equations;
2) Table 4: please rescale the equations, some of them are a little bit blurry;
3) What is your opinion regarding oxygen/ carbon contamination, which usually occurs in all experiments. Have you saw on your surface samples, the oxide layer, or you've managed to removed it?
Author Response
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Reviewer 2 Report
The paper deals with understanding the grain size strengthening and twin boundary strengthening of the non-equiatomic Ni2FeCr medium entropy alloy. Nowadays, the rapid development of high and medium entropy alloys is observed and thus there is a need to deepen the understanding of basic strengthening mechanisms governing these new types of metallic systems. In the current work, Authors developed new medium alloy system and studied in deep the fundamental mechanisms of grain boundary and twin boundary strengthening. The paper is well written, title is appropriate, the methods and experimental procedures are well described. Results are also well presented and deeply discussed. Conclusions are appropriate and reflect the findings presented in the paper. It is an example of solid work and I am sure that the paper will gain a lot of interest from the materials science community. In my opinion paper can be accepted after minor revision - there are some issues listed below:
Page 4; line 141: Please correct "dislocation ship" into "dislocation slip"
Page 4; line 142: Please correct "two different length scale" into "two different length scales"
Page 10; Figure 7: Please correct "crystallite size"
Page 10; line 326: yield stress for d=24 μm is decrease into "decreases"
Page 14; line 449: Please correct "The mainly crystallographic" into "The main crystallographic"
Author Response
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Reviewer 3 Report
1. Summary, strengths, weaknesses, overall contribution
Summary: In the paper the Authors prepared a novel Co-free non-equiatomic Ni2FeCr medium-entropy alloy. They also investigated the Hall–Petch strengthening by grain boundaries and annealing twin boundaries. The results are interesting and promising especially for development of novel materials for applications at elevated temperatures.
General strengths: From the scientific point of view the paper is very good. The innovative and important materials are studied. The discussion is detailed and the conclusions are properly formed.
General weaknesses: At first glance the paper does not have any general weakness. However, there are a few points which need clarification.
The paper should be accepted after minor revision. The authors may refer to the following remarks and do the corrections, which would improve the paper:
2. Major comments
- The range in grain size showed in Table 2 is rather narrow. Would it be possible to create and investigate at least one sample with significantly different grain size? It could strengthen the paper conclusions.
- What was the microstructure of the sample after cold rolling? Why the Authors have not perform annealing in much lower temperature for only stress relieving (not recrystallization). Probably, it would allow to obtain a sample with much smaller grains.
- Micro- or especially nanograin samples usually exhibit significant stress rate dependent yield strength. Why the Authors apply 1 × 10-3 s-1 stress rate and is there any influence of the strain rate on the presented results?
- How the measurement errors (indicated i.e. in Fig. 7) were estimated? Especially for the yield strength? How many samples of the same type were investigated? Are the results reproductive?
- Why 24 μm (crystallite size, c = 15 μm) sample was used for tensile tests at higher temperatures? The samples should further recrystallize during the test. How to distinguish the influence of further recrystallization and other high temperature effects on yield strength?
3. Minor comments
- In the introduction the Authors may also mention another class of High Entropy Alloys, which have superior thermomechanical properties – refractory HEAs. The following literature may be useful: DOI: 10.1002/adem.202101626; 10.1016/j.jallcom.2016.04.320;
Author Response
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Reviewer 4 Report
The reviewed manuscript entitled “Hall–Petch Strengthening by Grain Boundaries and Annealing Twin Boundaries in Non-Equiatomic Ni2FeCr Medium-Entropy Alloy” presents the Hall-Petch strengthening by grain boundaries and annealing twin boundaries for non-equiatomic medium-entropy alloy. The manuscript is well-prepared and clearly written. The authors thoroughly discuss the obtained results, leading the potential reader from figure to figure, discussing all results, and explaining phenomena found. I think that the manuscript should be published in the Journal after very minor amendments (some editorial errors given below):
1. Page 1, line 23: There given a shortcut/abbreviation “EBSD” without explanation (i.e. electron back-scattered diffraction). It should be explained even if it is a well-known abbreviation.
2. Page 3, lines 100-101: There are given samples’ names that differ from adequate ones in Table 1. I mean, there are 5 samples for 873 K, and one sample each for different values of temperatures (1023 K, 1173 K, 1323 K). In Table 1 and in the manuscript, there are 5 samples for 1023 K, and one sample each for different values of temperatures (873 K, 1173 K, 1323 K).
3. Page 3, Figure caption (#1): Add meanings of “RD”, “TD”, and “ND” in the figure caption.
4. Page 4, line 162: There is written: “(…) cleavage peak gradually disappears (…)”. I think that it will be better to write: “Moreover, the intensity of the cleavage peak decreases with increasing recrystallization temperature.”. One can easily notice some asymmetry of the {111} peak for CR-1323K/1h, leading to a conclusion that the intensity of that peak is small enough in comparison with the intensity of the {111} peak.
5. Page 5, Table 2: The errors should be added for the parameter “n”.
6. Page 9, line 300: I think it will be better to write “black and red” instead of “red and black”.
7. Page 10, Figure 7: There is “ctrscrystallite size” (the red color in the figure). A “ctrs” is unnecessary.
Author Response
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