Effect of cooling rates on the dendritic morphology transition of Mg–6Gd alloy by in situ X-ray radiography

Yongbiao Wang, Liming Peng, Yanzhou Ji, Xiaoxing Cheng, Cunlong Wang, Yujuan Wu, Yanan Fu, Long Qing Chen

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The effect of cooling rate on the transition of dendrite morphology of a Mg-6Gd (wt%) alloy was semiquantitatively analyzed under a constant temperature gradient by using synchrotron X-ray radiographic technique. Results show that equiaxed dendrites, including exotic ‘butterfly-shaped’ dendrite morphology, dominate at high cooling rate (>1 K/s). When the cooling rate decreases in the range of 0.5–1 K/s, the equiaxed-to-columnar transition takes place, and solute segregates at the center of two long dendrite arms (LDA) of the ‘butterfly-shaped’ dendrite. When the cooling rate is lower than 0.3 K/s, directional solidification occurs and the columnar dendritic growth direction gradually rotates from the crystalline axis to the thermal gradient direction with an increase in cooling rate. Meanwhile, interface moves faster but the dendrite arm spacing decreases. Floating, collision and rotation of dendrites under convection were also studied in this work.

Original languageEnglish (US)
Pages (from-to)1142-1148
Number of pages7
JournalJournal of Materials Science and Technology
Volume34
Issue number7
DOIs
StatePublished - Jul 2018

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Polymers and Plastics
  • Metals and Alloys
  • Materials Chemistry

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