The zinc-rich corner of the 450 deg C isothermal section of the Zn-Al-Fe-Si quaternary system

The 450 deg C isothermal section of the Zn-Al-Fe-Si quaternary system with Zn being fixed at 93 at.% has been studied experimentally by means of optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. Three Al-Fe-Si ternary phases, tau1, tau23 and tau, have been found in this section and the Zn solubility in those three phases are 6.9, 8.3 and 5.9 at.%, respectively. FeSi was found to be in equilibrium with FeSi2, Si, eta-Zn, tau1, zeta and tau. The Al solubility in the FeSi phase is 11.2 at.%, and that in the FeSi2 phase is rather limited. The Zn-Al-Fe ternary phase T(Fe8Al6Zn86) was found to be in equilibrium with eta-Zn, Fe2Al5 and tau1 phase. Experimental findings indicated the possibility of three-phase equilibrium between FeSi, FeSi2 and Si. The obtained isothermal section of Zn-Fe-Al-Si quaternary is compatible with the Zn-Al-Fe, Zn-Al-Si and Zn-Fe-Si ternary systems. Because of the lack of the precise Al-Fe-Si system phase relations at 450 deg C, the checking of the consistency with this system needs more works.