Dynamic recrystallization phenomena during laser-assisted friction stir processing of a precipitation hardened nickel base superalloy

摘要

Laser-assisted friction stir processing was used to modify the microstructure of an as-cast gamma prime strengthened nickel base superalloy. The grain structure of top region of the stir zone, where full dissolution of gamma prime precipitates occurred during heating, is controlled by discontinuous dynamic recrystallization mechanism and the pinning effect of refined carbides and cooling gamma prime precipitates. In the bottom of the stir zone, the partial dissolved gamma prime precipitates play important role in grain structure development by their pinning effect in retarding grain growth during cooling as well as by a continuous recrystallization mechanism. (C) 2016 Elsevier B.V. All rights reserved.