Statically recrystallized grain size as a function of prior stored energy level in the A-286 Fe-based superalloy

Abstract

A-286 alloy is a Fe-based superalloy used in various engines and gas turbine components. During manufacturing, this alloy is submitted to a solution heat treatment that provides good formability for the subsequent deformation steps. Hence, a good control of grain size evolution is required to avoid the formation of a broad grain size distribution or the growth of abnormally large grains. In this work, a well-controlled strain gradient has been generated by means of indentation tests at room temperature. A specific strain level, calculated by finite element simulations, and the associated dislocation density estimated by the EBSD technique, lead to the activation of selective grain growth during heat treatment after a given incubation time. This study on cold-deformed A-286 alloy allowed a quantitative assessment of recrystallized grain size dependence on stored energy and the identification of the critical stored energy value for grain nucleation, providing a better understanding of A-286 static recrystallization behavior.