In situ investigation on the precipitation of topologically close-packed phase in Ni-base single crystal superalloy

摘要

In situ transmission electron microscopy was first applied to study the precipitation behavior of topologically close-packed (TCP) phase at elevated temperature in Ru-free and Ru-containing Ni-base single crystal superalloys. Ru addition can decrease both the nucleation and growth rate, hence to suppress TCP precipitation effectively. Higher exposure temperature reduces the nucleation rate but increases the growth rate, finally accelerates the precipitation. The TCP phases nucleate homogeneously in y matrix without preferential sites, but tend to grow toward primary γ/γ' interface for element supply. An orientation relationship is kept during nucleation and growth of _μ phase in y matrix, which is [110]_μ // [001 ]_γ and(001)_μ//(-110)_γ.