TEM in-situ investigation on non-equilibrium eutectics in semicontinuous casting ingot of AI-6.2Zn-2.3Mg-2.3Cu super-high strength aluminum alloy

摘要

The in-situ investigation on morphology, chemical contents and crystal structure of non-equilibrium eutectics in semicontinuous casting ingot of Al-6.2Zn-2.3Mg-2.3Cu super-high strength aluminum alloy have been carried out by transmission electron microscopy equipped with energy dispersive X-ray spectroscopy (TEM-EDX). The results show that a large amount of lamellar non-equilibrium eutectics exists in semicontinuous casting ingot of this alloy; the non-matrix phase of this eutectics is a secondary phase which contains Al, Zn, Mg and Cu elements, with the atom ratio of approximately 1:1:1:1, and this non-matrix phase of non-equilibrium eutectics owns the same crystal structure as that of η phase (MgZn_2).