Fabrication of Bimetallic High-Strength Low-Alloy Steel/Si-Bronze Functionally Graded Materials Using Wire Arc Additive Manufacturing

Round 1

Reviewer 1 Report

The article brings important information to the researchers and the whole community dealing with WAAM and material characterization. In the literature survey, I miss the information about controlling the building of bimetallic parts using WAAM and post-processing i.e. machining of such parts. I suggest that authors check some of the following or other papers:

Online monitoring of wire arc additive manufacturing process: a review, EDI Azizul Izham, et al. - Advances in Materials …, 2023 - Taylor & Francis

Gas metal arc welding based additive manufacturing—a review, S Pattanayak, et al.  - CIRP Journal of Manufacturing Science and …, 2021 - Elsevier

In-process path replanning and online layer height control through deposition arc current for gas metal arc based additive manufacturing, A Ščetinec, et al.  - Journal of Manufacturing Processes, 2021 - Elsevier

A review on wire arc additive manufacturing: Monitoring, control and a framework of automated system, C Xia, et al. … - Journal of manufacturing …, 2020 – Elsevier

Multi-material additive manufacturing: A systematic review of design, properties, applications, challenges, and 3D Printing of materials and cellular …, A Nazir, et al. - Materials & Design, 2023 - Elsevier

A review of post-processing technologies in additive manufacturing, X Peng et al.  - … of Manufacturing and Materials …, 2021 - mdpi.com

Review on additive manufacturing of multi-material parts: Progress and challenges, S Hasanov, et al.  - … of Manufacturing and …, 2021 - mdpi.com

Machining Strategy Determination for Single-and Multi-Material Wire and Arc Additive Manufactured Thin-Walled Parts, OC Ozaner, et al. , Materials, 2023•mdpi.com

Post-processing techniques to enhance the quality of metallic parts produced by additive manufacturing, MA Mahmood, - Metals, 2022 - mdpi.com

Directed energy deposition (DED) additive manufacturing: Physical characteristics, defects, challenges and applications, D Svetlizky, … - Materials Today, 2021 - Elsevier

Abstract: Please, mention in your abstract that WAAM is appropriate method for FGM preparation of HSLA- Si-Bronze. (as a Key Findings in WAAM)

1)     Introduction:
Considering that the FGM is a multi-wire WAAM process, it would be better to mention the single-wire WAAM process in the introduction. Writing separately about WAAM-HSLA steel and WAAM-Si-Bronze in the literature review can enlighten the possible challenges of mentioned materials in WAAM process.

2)     2.1 Material Used and Building Strategy:

a)     Page 3,line 122 to 124 – correct the sentence (Two beads per layer...).

b)     Page 3, line122 to 125-  It would be better to show how one single bead welding of bronze wire covers two weld bead of HSLA.(optional)

c)     Page 3, Line 125 to 127 – Please clarify how interlayer alternate deposition results in uniform deposition at the end of wall.

d)     Page 4, Line 127 to 129, Please describe how 40 % overlap percentage of 5 mm bead width (BW) in HSLA, results in 8.5 mm average width.

e)     Page 4, table 1 – missing unit for chemical composition.

f)      Page 4, Figure 2,  add axes configuration (x,y,z)

 

3)     Characterization and Testing Techniques.

Microstructural Evolution:

a)     Page 5, line 171, Change the heading index number, it is repetitive. 

b)     Page 5, Figure 3, add axes configuration (x,y,z).

Mechanical Properties Characterization

c)     Page 7, Line 220 to 222-, Please specify the location of the bending in Si-Bronze zone compare to the middle of interface region.

d)     Page 8, Line 241, Check English throughout the article, (evidence is uncountable noun)

4)     Results and discussion
Microstructure evolution:

a)Page 9, Figure 7, It would be better to show 9 mm interface length.  
XRD:

a)     Please mention the chemical composition of compounds related to the ferritic and FCC ɛ-phase.

b)     Page 11, Lines 322 to 326, These sentences are repeated.

Hardness Measurements:

a)     Page 13, line 350 to 352, please add the positions of i to x from figure 7 to figure 13 for better comparison.

b)     Page 14, Figure 13, It would be better to indicate the length of the interface as 9 mm as a critical distance.

Conclusions

Could be improved

English editing can improve the information in the article.

Author Response

First, the authors of the work would like to express their gratitude and appreciation for the constructive input, comprehensive and helpful comments and remarks given by the reviewers, and queries that led to the enhancement of the manuscript. The requested modifications without doubt strengthened the manuscript and put it in the proper form necessary for its publication.
Second, the Response to each and every comment is given below it in red-colored italic-formatted font.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors developed bi-metallic HSLA Steel Si-Bronze functionally graded structures using wire and arc additive manufacturing. Microstructural evolution and mechanical properties are investigated. The work is overall good. However, there are some minor problems that the authors need to address before publication, including:

1-      Page 4, Lines 140-142: Please add an explanation on how the bead temperature was measured after the deposition of each layer using AMPROBE IR-750-EUR thermal gun. Was the thermal gun used manually by hand or was it mounted to the robot? Was there any delay time after the deposition and the measurements?

2-     The sample you represent in Figure 3, is that the only sample produced? Please comment on the reproducibility of the results. The major concern is the number of samples for mechanical testing. Usually, a minimum of 3 repeats is required.

3-      Please use a better picture for Figure 6. The picture quality is not good and seems blurry which affects the judgement of observable defects.

 

4-      Please explain how the wire switch is handled in your machine. Does the wire feeder switch between wires automatically or it has to be done by changing the wire roll in the machine? Was there any wait time for the wire switch? Please also comment on technology limitations for the wire switch and if feeding two wires at the same time is possible to achieve a smooth gradient is possible.

Author Response

First, the authors of the work would like to express their gratitude and appreciation for the constructive input, comprehensive and helpful comments and remarks given by the reviewers, and queries that led to the enhancement of the manuscript. The requested modifications without doubt strengthened the manuscript and put it in the proper form necessary for its publication.
Second, the Response to each and every comment is given below it in red-colored italic-formatted font.

Author Response File: Author Response.pdf