γ precipitation in the primary γ΄ of a new Ni–Co-base disc superalloy

The γ precipitation in the primary γ΄ of a new Ni–Co-base disc superalloy, TMW-4M3, has been investigated. It was found that 5 nm γ precipitates nucleated homogeneously in the primary γ΄ after solution heat treatment. The size of these tiny particles was unlikely to change after two steps aging treatment, but significant growth was detected after creep rupture at 725 °C under various stresses. The growth and/or coarsening process of γ precipitates can be described with the Lifshitz–Slyozov–Wagner (LSW) equation. The phase stability of γ precipitates and the influence of γ precipitation on the deformation of primary γ΄ are discussed.