Determination of the 76 wt.% Au section of the Al-Au-Cu phase diagram

The substitution of Al for Cu along the 76 wt.% Au section of the Al-Au-Cu system causes the α phase of the Au-Cu edge to be successively replaced by a ternary β electron compound, a ternary extension of the Cu-Al γ electron compound, designated here as γ', and finally the compound AuAl2. A vertical section of this part of the phase diagram has been determined and is presented here, and the relationships between the phases explored. It is considered likely that the section contains the peritectic reactions L+α→β and L+γ'→β. Both the α and the β phases form ordered phases at lower temperatures