You are welcome for my question!however it's for me to thank you for you response. Did you work in this subject? how to quantify the twins in magnesium alloys and how to produce it?
SCOPUS gives a lot of references to the papers devoted twinning in magnesium alloys during FSW, e. g.
Xu, N., Song, Q., Fujii, H., Bao, Y., Shen, J. Mechanical properties’ modification of large load friction stir welded AZ31B Mg alloy joint (2018) Materials Letters, 219, pp. 93-96.
Xu, N., Song, Q., Jiang, Y., Bao, Y., Fujii, H. Large load friction stir welding of Mg–6Al–0.4Mn–2Ca magnesium alloy (2018) Materials Science and Technology (United Kingdom), pp. 1-13. Article in Press.
Liu, Z., Xin, R., Wu, X., Liu, D., Liu, Q. Improvement in the strength of friction-stir-welded ZK60 alloys via post-weld compression and aging treatment (2018) Materials Science and Engineering A, 712, pp. 493-501.
Shang, Q., Ni, D.R., Xue, P., Xiao, B.L., Ma, Z.Y. Improving joint performance of friction stir welded wrought Mg alloy by controlling non-uniform deformation behavior (2017) Materials Science and Engineering A, 707, pp. 426-434.
Mironov, S., Onuma, T., Sato, Y.S., Yoneyama, S., Kokawa, H. Microstructural changes during tension of friction-stir welded AZ31 magnesium alloy (2017) Materials Characterization, 130, pp. 1-8.
Gao, X., Zhang, Z., Wang, W., Hai, M., Jia, S., Wang, K. Superplasticity of fine-grained AZ31 magnesium alloy prepared by friction stir processing (2016) Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering, 45 (7), pp. 1855-1860.