Browsing by Author "StJohn, David H."

Now showing items 1-5 of 6

  • Effect of iron on grain refinement of high-purity Mg–Al alloys

    Cao, Peng; Qian, Ma; StJohn, David H. (Elsevier Ltd, 2004-07)
    The effect of iron on the grain refinement of high-purity Mg–3%Al and Mg–9%Al alloys has been investigated using anhydrous FeCl3 as an iron additive at 750 °C in carbon-free aluminium titanite crucibles. It was shown that ...
  • Effect of manganese on grain refinement of Mg–Al based alloys

    Cao, Peng; Qian, Ma; StJohn, David H. (Elsevier, 2006-06)
    Manganese is a grain refiner for high purity Mg–3%Al, Mg–6%Al, Mg–9%Al, and commercial AZ31 (Mg–3%Al–1%Zn) alloys when introduced in the form of an Al–60%Mn master alloy splatter but the use of pure Mn flakes and ALTAB™ ...
  • Grain coarsening of magnesium alloys by beryllium

    Cao, Peng; Qian, Ma; StJohn, David H. (Elsevier Ltd, 2004-10)
    A trace of beryllium can lead to dramatic grain coarsening in Mg–Al alloys at normal cooling rates. It is, however, unclear whether this effect applies to aluminium-free magnesium alloys or not. This work shows that a trace ...
  • Mechanism for grain refinement of magnesium alloys by superheating

    Cao, Peng; Qian, Ma; StJohn, David H. (Elsevier, 2007-04)
    The mechanisms for grain refinement of magnesium alloys by superheating have remained ambiguous since 1931. A model has been proposed on the basis of the recent understanding of the grain refinement of both high purity and ...
  • Native grain refinement of magnesium alloys

    Cao, Peng; Qian, Ma; StJohn, David H. (Elsevier Ltd, 2005-10)
    High purity Mg–Al type alloys have a naturally fine grain size compared to commercial purity alloys with the same basic composition. This is referred to as native grain refinement. It is shown that native grain refinement ...

David H. StJohn has 3 co-authors in Research Commons.