Phase Equilibria of the Mg-Zn-Sm System in Mg-Rich Corner at 320 °C and 400 °C

Round 1

Reviewer 1 Report

This manuscript presents an interesting work of high quality. I only have one minor recommendation conserning the position of Table 2. The authors should consider moving the table to the top of the Results section to facilitate reading the first paragraph of that section.

Author Response

Thank you for your comments and suggestions. The Table 2 was moved to the top of the Results section. Please see lines 98-100 in the latest vision of manuscript.

Reviewer 2 Report

Why intermetallic compound Mg3Sm has the peaks with the maximum intensity ? it is higher that that of for Mg solution.  How the material for XRD was collected? Did you analyze the effect of texture and peaks shifts due to non-equilibrium solubility of the alloying elements.

 

Author Response

Thank you for your professional and rigorous comments. 

Point 1: Why intermetallic compound Mg₃Sm has the peaks with the maximum intensity ? it is higher than that of for Mg solution.  

Response 1: The maximum intensity of Mg₃Sm could be attributed to its higher weight fraction in the as-cast alloys #1 and #2. Figure 1a and b shows that volume fractions of both Mg₃Sm and Mg solution are almost the same. However, the density of Mg₃Sm is nearly twice as much as Mg.

Point 2: How the material for XRD was collected?

Response 2: All the XRD patterns in this work were collected from the powder samples. The blocky alloys were crushed into powder and then sifted by 200 mesh sieve after ground. This part have been revised in the latest manuscript. Please see lines 88-90.

Point 3: Did you analyze the effect of texture and peaks shifts due to non-equilibrium solubility of the alloying elements?

Response 3: The powder samples for XRD can minimize the texture. Therefore, the effect of texture was not considered in this work. The non-equilibrium solubility of Zn atoms was found to influence the diffraction peaks of Mg₃Sm. For example, the solubility of Zn in Mg₃Sm in as-cast alloy #1 was measured to be 16.7 at.%. after annealing at 320 ℃ and 400 ℃, the Zn contents of Mg₃Sm increase up to 28.3-30.2 at.%. Correspondingly, the diffraction peaks of Mg₃Sm in the annealed alloy #1 shifts to higher angle.

Reviewer 3 Report

In the manuscript there are often found descriptions of areas, e.g. Mg+Mg₄₁Sm₅+Mg₃Sm, Mg+Mg₃Sm+Z et cetera. In fact, in these areas there is no pure magnesium but a magnesium-based solid solution because both zinc and samarium dissolve slightly in magnesium. Therefore, it would be better to write e.g. (Mg)+Mg₄₁Sm₅+Mg₃Sm, (Mg)+Mg₃Sm+Z et cetera. It can also be explained in the introduction that it was done for the sake of simplicity.

Author Response

Thank you for your professional and rigorous suggestion. According to your suggestion, all the “Mg” occurring in the descriptions of areas have been replaced with (Mg) seen in the revised manuscript.