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  • 1 Université de Toulon et du Var Laboratoire de Physico-Chimie du Matériau et du Milieu Marin, Matériaux à Finalité Spécifique (E.A. 1356) B.P. 132 83957 La Garde cedex France B.P. 132 83957 La Garde cedex France
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Abstract  

The Al-Zn-Ga ternary phase diagram was earlier established by thermodynamic modellization [1], but no experimental study appears to have been carried out on this system, except for measurements of mixing enthalpies in the liquid [2]. The present experimental study was carried out by thermal analysis and X-ray diffraction at various temperatures, using the isopletic cuts method. Four isopletic cuts were established and two others were partly studied in the Al-rich corner of the diagram. On these cuts, two isobaric ternary invariant reactions were determined: a eutectic reaction at 231C, and a metatectic reaction at 1231C. Evidence was found for the existence of a retrograde miscibility of Ga in a solid solution α′SS which protrudes into the ternary system starting from the Al-Zn binary up to a Ga concentration of about 30%*.