Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties
, Valeriy Kostikov 2, Zhanna Eremeeva 2, Svetlana Savushkina 1, Boris Ivanov 1, Dmitriy Khmelenin 3, Gleb Belov 4 and Yuri Solyaev 5Round 1
Reviewer 1 Report
Comments are described inside upladed file
Comments for author File: 
Comments.pdf
Author Response
All grammatic and syntax corrections were done.
Information about heating and cooling rates, pressure-time stages, sample proportions was added.
Quality of figures 2,5,7 was improved.
The sentence, that you didn’t understand was rewritten. 'The tensile strength of sintered nickel increases by 10-40 % with an increase of nanofibers content in the range of 0.01-0.1 wt. % at room temperature'
Reviewer 2 Report
The research contents of the manuscript are new, reporting a preparation of Ni bulk sample by SPS by activated Ni powder with nanosized Al2O3 fiber of 0, 0.01, 0.0225, 0.05 and 0.1 wt.%. The mechanical properties show a remarkable change in mechanical properties. The results are valuable, however, insufficient explanations have been to support their valuable explanations before to consideration of this manuscript to publishing at Metals.
Abstract: Whole abstract needs to be rewritten to attract the reader.
2. Materials and Methods section:
- the term "in steel glasses" should be "in steel jars" or "in steel vials".
- the term "P:B" shoudl be in details as "Powder:Ball".
- For SPS operation, please provide heating rate and type of sintering mold (graphite or WC).
- The dimension of tensile test sample should be indicated in this section.
3. Results and 4. Discussion
The line style in Figure 2 should be change to clearer visible with black/white print.
Figure 3 do not present enough quality (format, size, micron scale, ..).
The subtitle 3.3 should be “Tensile strength”.
The authors should use the correct terms of “Young modulus”, “tensile strength” for “Elastic modulus (this is for Young, Shear and bulk modulus)” and “sample strength”, "nickel strength".
5. Conclusions
The conclusions need to be rewritten for precise for obtained results.
References
Please revise all the references and following the journal style. DOIs should be included.
Author Response
Abstract was rewritten with additional information about research.
All your wishes for part 2 and 3 of manuscript were done.
Conclusions were rewritten with additional info about microstructure and nanofibers impaction.
References were added with DOIs and revised.
Reviewer 3 Report
This is a very interesting work. I recommend an improvement of Fig. 2 by showing data points and error bars and not only the fit curves. From which area is Fig 7 b taken? More explanation is ecpected.
Author Response
Figure 2 was changed.
Figure 7 were added with area of which the diffraction pattern was taken, and with explanation. 'The diffraction pattern, taken from sample area in figure 7a, shows that the material is polycrystalline (Figure 7 b). It looks like there are phases that may be contained in sintered material, like Al2O3 (rings №№ 1,2,4-7,10-12), Ni (rings №№ 7-10,12), NiO (rings №№ 11,12).'
Reviewer 4 Report
The submitted manuscript entitled “Influence of alumina nanofibers on the nickel mechanical properties sintered by the spark plasma method” has some interesting results. The authors conducted comprehensive studies, starting from microstructure studies, ending with tensile strength properties.
It's just a question rather than a comment, but I am interested in the mechanism of grinding nickel grain with the addition of alumina nanofibers.
Author Response
It’s not a grinding, it’s protection from recrystallization. The information was added. 'This is due to the fact that nanofibers are playing role of obstacles to the recrystallization of nickel grains during sintering.'
Reviewer 5 Report
The manuscript is interesting and could be accepted after a minor revision.
- The figures need to be refined to enhance the resolution and quality;
- The alumina fiber might be gama phase and how about the phase transformation during sintering.
Author Response
Figures were improved.
It’s known that the alumina nanofibers are very stable till 1200 oC. But I think, that SPS could help to transform gamma-phase to delta with temperature value, that we chose. It’s needed some additional study to prove it.
