Microstructure Evolution and Properties of Hastelloy UNS N06200 and UNS N06022 as a Function of the Applied Thermal Treatment

The aim of this study is focused on the mechanical and the microstructural characterization of two Ni-based cast alloys: Hastelloy UNS N06200 and Hastelloy UNS N06022. The analysis has been performed through the observation of different microstructures obtained as a function of different cooling rates performed by the use of test blocks. After solidification, the specimens produced by different cooling rates have been extracted, and UNS N06200 samples have undergone a solution treatment process, while UNS N06022 samples have undergone a solution treatment followed by an ageing process. The mechanical properties have been measured, and some significant and consistent relationships have been pointed out with the heat treatment and the obtained microstructures.