Detectable Depth of Copper, Steel, and Aluminum Alloy Plates with Pulse-Echo Laser Ultrasonic Propagation Imaging System

Round 1

Reviewer 1 Report

The submitted manuscript needs major revision in order to be published:

- The terms “A scan data, C scan data, A scan graphs, C scan images, A scan process, C scan process are used in the text without sufficient explanation”

- Pages 3, 4; lines 89 – 103: Chemical composition of the tested materials should not be defined only by the standards (it means "must be"), but by their real chemical analysis.

- The interpretation and discussion of the obtained results is missing: Experimental results are only described, but they are not interpreted and discussed in the perspective of previous studies. No relations between the properties of the tested materials and the results obtained are assessed.

Author Response

Thank you for your cooperation.

We have answered all of comments.

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Pulse-echo laser ultrasonic propagation imaging is a nondestructive testing technology for aerospace composites and aluminum alloys. In this paper, the material defect detection of this technology is carried out, and some specific test results are used to verify the characteristics of this technology. This study is very important for the detection of the internal condition of metal materials.

However, I was wondering how to extend the detection range of this technology, such as greater depth and greater accuracy, because some advanced processing methods, such as selective laser melting, require the detection of defects at the micron level. In addition, some processing methods also involve real-time detection requirements, such as laser welding.

Author Response

Thank you for your cooperation.

We have answered your comment.

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

In my opinion, the paper was sufficiently corrected according to the reviewers' comments.  I recommend to accept it for publication.