Refinement of primary silicon of hypereutectic Al-Si alloys by ultrasonic radiation and its application for die castings

Kazuhiro Oda, Sergey Komarov, Yasuo Ishiwata

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The study purpose is to investigate effects of ultrasonic radiation on refinement of primary Si crystals of hypereutectic Al-Si alloys and to examine the refining effect in die casting. The ultrasonic refining effect was examined by using Al-Si alloys without or with addition of phosphorus. The experiments included melting of alloy in a crucible, radiation of ultrasound into the melt at temperatures at least 60 K higher than the Si crystallization temperature, holding of the melt for 20-80 s and pouring of it into a Cu mold by gravity casting. The refining effect was found to be dependent on P content and holding time. The EPMA investigation revealed that the ultrasonic radiation increases the number of AlP particles acting as heterogeneous sites for the primary Si nucleation. The refining effect was significant at the holding time of 20-50 s. Then, based on the above results, the radiation conditions for the die casting were determined. A key point of the conditions was that the refining effect and melt fluidity are kept at the desired level for a period after the radiation. Microstructural investigation showed considerable refinement of primary Si crystals and Al-Fe-Mn-Si compounds. The ultrasonically treated die castings exhibited an improved tensile strength.

Original languageEnglish
Pages (from-to)149-154
Number of pages6
JournalKeikinzoku/Journal of Japan Institute of Light Metals
Volume61
Issue number4
DOIs
Publication statusPublished - 2011 Jun 8
Externally publishedYes

Keywords

  • Al-Si alloy
  • Die casting
  • Primary silicon
  • Refinement
  • Ultrasonic radiation

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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