Hydrogen, porosity and oxide film defects in liquid Al

William Griffiths, R Raiszadeh

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


This article reports results from an experiment where a bubble of air was held at a constant temperature in a liquid Al melt, with the volume of the bubble monitored continuously using real-time X-ray equipment. When the H content of the surrounding melt was low, the volume of the trapped air bubble reduced with time, as the O and N in the bubble atmosphere reacted with the Al to form Al2O3 and AlN. When the H content of the melt was increased to about 0.3 ml 100 g(-1) Al, the H in solution passed into the air bubble causing its expansion. In an Al casting the same effect would cause an entrained double oxide film defect to act as a site for the growth of H-driven gas porosity. The way in which the oxide film defects might behave in forming H porosity has been discussed.
Original languageEnglish
Pages (from-to)3402-3407
Number of pages6
JournalJournal of Materials Science
Issue number13
Publication statusPublished - 1 Jul 2009


  • PEPT
  • shape casting
  • Positron Emission Particle Tracking
  • radioactivity
  • Inclusions


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