|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Deformation and Damage Mechanisms in High Temperature Ni, Co and Fe-based Superalloys
||Heteroepitaxial Recrystallization in Polycrystalline Nickel-based Superalloys: Nucleation Mechanism
||Marie-Agathe Charpagne, Jonathan Cormier, Timothy J. Clark, Tresa M. Pollock
|On-Site Speaker (Planned)
In polycrystalline nickel-based superalloys, the control of grain size distribution is crucial for achieving the required fatigue and creep properties. Therefore, understanding the fundamental mechanisms of microstructure evolution is of great interest.
A new recrystallization mechanism – heteroepitaxial recrystallization- has recently been reported in several nickel-based superalloys. In this mechanism, each primary gamma prime precipitate gives rise to a unique recrystallized grain of the same crystallographic orientation. Those singularities result from an uncommon nucleation mechanism, which still remains to be understood.
Heteroepitaxial recrystallization is always preceded by the formation of a coherent shell of gamma phase around primary y’ precipitates, usually prior to deformation. The conditions of formation of such gamma phase are investigated in terms of driving forces, segregation of elements and influence of the density of defects in the gamma prime precipitates.
||Planned: Supplemental Proceedings volume