A microanalytical study of the early stages of recrystallization in the nickel-base superalloy APK1

Analytical electron microscopy has been used to investigate the composition of various microstructural features in a powder-produced nickel-base superalloy. Specifically, it is shown that in the early stages of recrystallization the strain-free grains are depleted in theγ′-forming elements (i.e. titanium and aluminium). This observation is consistent with the hypothesis that recrystallization in this alloy is initiated in the immediate vicinity of large intergranularγ′ particles. It is also shown that the composition ofγ′ can be written as (Ni, Co)3 (Al, Ti, Cr).