QUANTITATIVE DESCRIPTION OF THE SUBSTRUCTURE OF HOT-DEFORMED A-286 SUPERALLOY

The influence of initial soaking and parameters of hot plastic working on the substructure of the A-286 superalloy have been presented. The research was performed on a torsion plastometer in the range of temperature 900 – 1150 °C, at a strain rates of 0.1 s -1 and 1.0 s -1 . The structural inspections were performed on longitudinal microsections taken from plastometric samples after so-called “freezing”. The examination of the microstructure was carried out, using transmission electron microscopy (TEM). Direct measurements on the TEM micrographs allowed the calculation of substructural parameters: the mean subgrain area, and the mean dislocation density. An analysis of the examination results of the alloy substructure revealed dynamic recovery, recrystallization and repolygonization, occurring consecutively in the course of hot deformation. A detailed investigations has shown that substructure of alloy is inhomogeneous, consists of dense dislocation walls, subgrains and recrystallized regions.