Characterisation of the 3-D dendrite morphology of magnesium alloys using synchrotron X-ray tomography and 3-D phase-field modelling. (15th June 2015)

• Record Type: Journal Article
• Authors: Yang, M.; Xiong, S.-M.; Guo, Z.
• Is Part Of: Acta materialia. Volume 92(2015)
• Page Start: 8
• Page End: 17
• Publication Date: 2015-06-15
• Subjects: Dendrite formation -- Magnesium alloys -- Synchrotron X-ray tomography -- Phase-field modelling; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2015.03.044
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: The 3-D morphology of α-Mg dendrites for Mg−30 wt.% Sn and Mg−30 wt.% Gd alloys was investigated and characterised using the synchrotron X-ray tomography technique. Results show that the α-Mg dendrites had eighteen primary branches with six growing along 〈 1 1 2 ¯ 0 〉 directions in the { 0 0 0 1 } basal plane and twelve along 〈 1 1 2 ¯ 3 〉 directions in the non-basal plane. The 〈 1 1 2 ¯ 0 〉 -oriented branches had secondary arms in four directions with two in 〈 1 1 2 ¯ 0 〉 and two in 〈 1 1 2 ¯ 3 〉, whereas the 〈 1 1 2 ¯ 3 〉 -oriented branches had secondary arms in three directions with one in 〈 1 1 2 ¯ 0 〉 and two in 〈 1 1 2 ¯ 3 〉 . By combining and modifying certain terms of spherical harmonics, an anisotropy growth function was developed for the first time to describe the growth of an eighteen-branch α-Mg dendrite. The 3-D phase field simulations were then performed and great agreement was achieved between the simulation results and experiment on various key growth aspects including dendrite morphology and side-branching patterns.