Experimental determination of 800 degrees C isothermal section in Al-Zn-Zr ternary system

The 800 degrees C isothermal section in the Al-Zn-Zr system was investigated using the equilibrated alloy method and the solid/liquid diffusion couple approach by means of scanning electron microscopy equipped with energy dispersive spectroscopy, X-ray powder diffraction and electron probe microanalysis. Thirteen three-phase regions are experimentally confirmed in the ternary system. A ternary compound Zn50Al25Zr25 named as T phase exists stably in the 800 degrees C isothermal section. Its composition range varies widely (16.84-55.1 at.% Zn, 18.02-56.3 at.% Al and 26.0-28.53 at.% Zr), and it can be in equilibrium with all the binary compounds. The maximum solubilities of Zn in Zr3Al, Zr2Al,Zr3Al2,Zr4Al3, ZrAl,Zr2Al3,ZrAl2 and ZrAl3 are 7.5, 0.84, 0.33, 0.89, 0.91, 1.12, 0.64 and 3.8 at.%, respectively. The maximum solubilities of Al in Zn3Zr,Zn2Zr and ZnZr are 1.6, 1.3 and 13.6 at.%, respectively.