Experimental study of ordering kinetics in aluminum alloys during solidification

N. Iqbal, N. H. Van Dijk, V. W.J. Verhoeven, W. Montfrooij, T. Hansen, L. Katgerman, G. J. Kearley

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

The microscopic structure and crystallization behavior of liquid Al and Al-0.3Ti-0.02B (wt.%) are studied by time-resolved neutron diffraction measurements during the liquid-solid phase transformation for continuous cooling. A specially developed furnace insert was used to obtain a temperature stability of 40 mK in the vicinity of the solidification temperature of To=933 K. The evolution of the static structure factor S(Q) has been monitored during the liquid to solid phase transformation as a function of the cooling rate. The evolution of the liquid fraction fL during the transformation is determined from the value of the first peak in the liquid structure factor. The evolution of the solid volume fraction fS=1-fL is analyzed in terms of the Johnson-Mehl-Avrami model. The Avrami exponent n is found to change for pure Al as well as for Al-0.3Ti-0.02B alloy with cooling rate and the rate constant k decreases by an order of magnitude for Al-0.3Ti-0.02B alloy compared to pure Al. Anomalous temporal oscillations were observed in the Bragg peak intensity of the solid grains during the solidification of the Al-0.3Ti-0.02B alloy.

Original languageEnglish
Pages (from-to)4497-4504
Number of pages8
JournalActa Materialia
Volume51
Issue number15
DOIs
Publication statusPublished - 3 Sept 2003
Externally publishedYes

Keywords

  • Aluminum alloys
  • Neutron diffraction
  • Solidification
  • Structure factor
  • TiB

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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