Modification of eutectic Si in Al-Si based alloys

Jiehua Li*, Mihaela Albu, T.H. Ludwig, Y. Matsubara, Ferdinand Hofer, L. Arnberg, Y. Tsunekawa, P. Schumacher

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract



The paper provides a new insight into the modification of eutectic Si in Al-Si based alloys. To date, impurity-induced twinning mechanism and twin plane re-entrant edge mechanism are the well-accepted theories. However, neither IIT nor TPRE can be used to interpret all modification observations. Therefore, a re-consideration of modification mechanisms is still required. In this contribution, recent advances on the understanding the modification of eutectic Si are reviewed. Two different cases are highlighted. In the case of Sr, Na and Eu addition, eutectic Si was modified from a faceted to a fibrous morphology, which involves the formation of multiple Si twinning. In the case of Yb and Ca addition, eutectic Si was refined to a smaller size, but still maintained a plate-like morphology. The possible modification mechanism was thus discussed in terms of (i) adsorption of atoms at twin re-entrant edge, and (ii) segregation across {111}Si growth planes. Furthermore, solute entrainment of modifying elements (M) was introduced to interpret the formation of Al2Si2M phase or M-rich clusters within Si crystals.
Original languageEnglish
Pages (from-to)130-136
JournalMaterials Science Forum
Volume794-796
DOIs
Publication statusPublished - 2014

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Application
  • Experimental

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