The ternary system aluminum-gold-silicon

Abstract

We calculated the two pseudobinary systems Al 2AuSi and AlAu 2Si and the Si liquidus surface at 1373 K. The AlAu and AlSi binary systems reported by Massalski and Hultgren agree with each other, but differences are present in the AuSi system. In the AlSi system the Si liquidus extends over a temperature range of 800 K, and in the AuSi system over 1000 K. This permits us to check the new equation for the difference in Gibbs energy G(l-s) and specific heat C p (l-s) derived from the consideration of T glass, the theoretical glass transition temperature. For the liquid solutions we used the Hoch-Arpshofen model. The only available ternary experimental data are the Si liquidus compositions at 1373 K obtained by Lozovdkiy and Politova. The agreement between experimental and calculated data is very good. The calculated eutectic compositions and temperatures are as follows: for the 1 3 Al 2AuSi system a eutectic temperature of 1.195 and an Si content x = 0.175; for the 1 3 AlAu 2Si system a eutectic temperature of 0.760 and an Si content x = 0.113.