Effects of aging treatments on the Microstructure of the Ni‐base superalloy IN‐738

Abstract
The effects of aging treatments on the microstructure of the Ni‐base superalloys IN‐738 HC and IN‐738 LC were investigated. Changes in (i) size, morphology, and distribution of the γ′‐phase, (ii) the amount of M23C6‐carbide, and (iii) the occurrence of additional phases and phase instabilities were quantitatively determined. The results indicate the possibility to deduce an unknown thermal history from the observed microstructure.