Migration of solidification grain boundaries and prediction

Hongmei Liu; Shenglu Lu; Yingbo Zhang; Hui Chen; Yungui Chen; Ma Qian

doi:10.1038/s41467-022-33482-8

Migration of solidification grain boundaries and prediction

Nat Commun. 2022 Oct 7;13(1):5910. doi: 10.1038/s41467-022-33482-8.

Authors

Hongmei Liu^{1

2

3}, Shenglu Lu⁴, Yingbo Zhang⁵, Hui Chen⁵, Yungui Chen⁶, Ma Qian⁷

Affiliations

¹ School of Materials Science and Engineering, Southwest Jiaotong University, 610031, Chengdu, China. lhm@home.swjtu.edu.cn.
² School of Materials Science and Engineering, Sichuan University, 610065, Chengdu, China. lhm@home.swjtu.edu.cn.
³ Department of Chemical and Materials Engineering, The University of Auckland, Auckland, 1010, New Zealand. lhm@home.swjtu.edu.cn.
⁴ Centre for Additive Manufacturing, School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia.
⁵ School of Materials Science and Engineering, Southwest Jiaotong University, 610031, Chengdu, China.
⁶ School of Materials Science and Engineering, Sichuan University, 610065, Chengdu, China.
⁷ Centre for Additive Manufacturing, School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia. ma.qian@rmit.edu.au.

Abstract

Solidification processing is essential to the manufacture of various metal products, including additive manufacturing. Solidification grain boundaries (SGBs) result from the solidification of the last liquid film between two abutting grains of different orientations. They can migrate, but unlike normal GB migration, SGB migration (SGBM) decouples SGBs from solidification microsegregation, further affecting material properties. Here, we first show the salient features of SGBM in magnesium-tin alloys solidified with cooling rates of 8-1690 °C/s. A theoretical model is then developed for SGBM in dilute binary alloys, focusing on the effect of solute type and content, and applied to 10 alloy systems with remarkable agreement. SGMB does not depend on cooling rate or time but relates to grain size. It tends to occur athermally. The findings of this study extend perspectives on solidification grain structure formation and control for improved performance (e.g. hot or liquation cracking during reheating, intergranular corrosion or fracture).