Micromorphology, Microstructure, and Wear Behavior of AISI 1045 Steels Irregular Texture Fabricated by Ultrasonic Strengthening Grinding Process
, Zhaoyang Liu 1,2, Xiaochu Liu 1,2,* and Ruizhi Tang 2
Round 1
Reviewer 1 Report
The paper is devoted to ultrasonic shot peening treatment of AISI 1045 steel to improve its surface mechanical properties. The authors performed many tests such as nanoindentation, SEM, surface microtopography and roughness by light interferometer, EBSD and wear test. These data provide readers with many sample comparing characteristics after polishing and ultrasonic treatment. All data confirm the superiority of USP and USGP treated samples compared to the polished ones. However, it should be noted that the surface roughness increases more than twice after ultrasonic treatment, which in some application cases might be critical. The microhardness increase is quite modest, compared to the other surface engineering techniques mentioned in the introduction such as surface alloying, surface coating, etc. There are no data for the wear resistance improvement. Generally, the application prospective of the proposed technique is questionable, especially for the details with the complex configuration. So, the hypothesis of “potential to be widely used for surface texturing and improving the fatigue life of the materials” should be supported by examples of the potential application.
Besides, the following remarks and comments are kindly advised to be reviewed.
1. It is necessary to put any numerical values in the abstract “Furthermore, these behaviors improved the surface microhardness and elastic modulus.” Please, provide the rate of microhardness and elastic modulus improvement compared to polishing.
2. Unproven assumptions are usually omitted. The dislocations and enhancing wear resistance, as it goes in the paper: “The results demonstrated that the transformation of the alpha iron phase to Fe3C occurred during USGP and USP, the dislocation pile-up distributed around the Fe3C, which resulted in the increase of cementite and kernel average misorientation.” and “Additionally, many irregular micro-dimples occurred on the machined surface, which can store the abrasive particles and further enhance the wear resistance ability of materials.” should be skipped or proved.
The dislocation presence should be confirmed by XRD (modified Williamson-Hall plots) or TEM images.
3. Please, use lower case for Fe3C as Fe3C in the abstract and throughout the paper.
4. It is necessary to rewrite the abstract according to the aforementioned comments.
5. Row 74. Put AISI instead of ISI.
6. How many samples were tested after each treatment to collect statistics and get median values?
7. Table 1. Please, check the chemical composition of AISI 1045 steel. According to which standard the elemental ratio was taken?
8. Row 88. Heat treatment: why tempering temperature was 180 C°? Please, specify the purpose of the low-temperate treatment.
9. Row 106-107. The reviewer recommends naming samples according to the treatment abbreviation as USP sample, USGP sample and polished sample instead of PT, SG and SP.
10. Figure 2a should be magnified.
11. Row 124. Please, use “X-ray diffractometer” instead of “X-ray diffraction spectroscope.”
12. Row 125. Please, check the model and producer title carefully “Rigaku+UltimaIV, Neo-confucianism Rigaku Inc., Japan”
13. Row 127. Please, provide the model of the Electron back-scattered diffraction.
14. Figure 10. Which phase can be attributed to the new diffraction peaks on the sample after USGP?
15. Row 222 and row 308. What was the mechanism of the alpha iron phase transformation into Fe3C? How the carbon shortage was compensated during this transformation?
16. Row 308. Replace FeC3 by Fe3C.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
I can recommend the publication of the manuscript after a minor revision.
Lines 85-91: Explain why you choose these values. Are these ones optimal?
Insert all the SEM parameters, such as magnification, acceleration voltage, working distance, and image pixel resolution.
Lines: 148-149, 200-201, 273-275; 286-288 - give more details.
Line 176: "The surface roughness Ra" is "Arithmetic mean height Ra" parameter.
If possible, can you specify some microtexture parameters for the samples such as: a) Height parameters: Root mean square height Sq [nm]; Skewness Ssk [-]; Kurtosis Sku [-]?
Kindly insert a paragraph with Statistical analyses, and explain the method, the software used, and all the parameters related to these statistical experiments.
Line 306: minor mistake: “...... 168.99 Gpa,...”
Line 310 - ... the lowest coefficient (<0.8)..... – specify correctly the coefficient.
If possible, I recommend these references:
1) DOI: 10.1002/jemt.24096.
2)Advances in manufacturing analysis: fractal theory in modern manufacturing. In “Modern Manufacturing Processes”, 1st edition, section 1, chapter 2, pages 13-39. DOI: 10.1016/B978-0-12-819496-6.00002-6. Publishing Reviews: Mechanical Engineering Series - an imprint of Elsevier, United States of America, 1st June 2020, 246 pages. ISBN: 978-0-12-819496-6 (print). ISBN: 978-0-12-822774-9 (online).
This paper presents an interesting approach and deserved to be published after the mentioned revisions.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you for addressing all the commenrs.
