Eutectic Modification of Al-Si Alloys with Rare Earth Metals

Kazuhiro Nogita, Stuart D. McDonald, Arne K. Dahle

Research output: Contribution to journalArticle

117 Citations (Scopus)

Abstract

The effects of different concentrations of individual additions of rare earth metals (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) on eutectic modification in Al-10mass%Si has been studied by thermal analysis and optical microscopy. According to the twin-plane reentrant edge (TPRE) and impurity induced twinning mechanism, rare earth metals with atomic radii of about 1.65 times larger than that of silicon, are possible candidates for eutectic modification. All of the rare earth elements caused a depression of the eutectic growth temperature, but only Eu modified the eutectic silicon to a fibrous morphology. At best, the remaining elements resulted in only a small degree of refinement of the plate-like silicon. The samples were also quenched during the eutectic arrest to examine the eutectic solidification modes. Many of the rare-earth additions significantly altered the eutectic solidification mode from that of the unmodified alloy. It is concluded that the impurity induced twinning model of modification, based on atomic radius alone, is inadequate and other mechanisms are essential for the modification process. Furthermore, modification and the eutectic nucleation and growth modes are controlled independently of each other.

Original languageEnglish
Pages (from-to)323-326
Number of pages4
JournalMaterials Transactions
Volume45
Issue number2
DOIs
Publication statusPublished - Jan 1 2004

Fingerprint

Rare Earth Metals
eutectics
Eutectics
Rare earths
rare earth elements
Metals
metals
Silicon
Twinning
twinning
solidification
Solidification
silicon
Rare earth additions
Impurities
impurities
radii
Growth temperature
Rare earth elements
Thermoanalysis

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Eutectic Modification of Al-Si Alloys with Rare Earth Metals. / Nogita, Kazuhiro; McDonald, Stuart D.; Dahle, Arne K.

In: Materials Transactions, Vol. 45, No. 2, 01.01.2004, p. 323-326.

Research output: Contribution to journalArticle

Nogita, Kazuhiro ; McDonald, Stuart D. ; Dahle, Arne K. / Eutectic Modification of Al-Si Alloys with Rare Earth Metals. In: Materials Transactions. 2004 ; Vol. 45, No. 2. pp. 323-326.
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