Dynamic Recrystallization Mechanisms of As‐Extruded GH4151 Alloy during Hot Deformation

Abstract

The new nickel‐based superalloy has a higher content of γ' strengthening phase, resulting in complex microstructure evolution during the hot forming process of the alloy. Thus the microstructure and properties are difficult to control, stable processing and forming cannot be achieved. Therefore, this paper investigates the effect of different deformation strains on the microstructure evolution and deformation mechanism of as‐extruded GH4151 nickel‐based superalloy using isothermal hot compression. As a result, the average grain size decreases with the increase of deformation, and the proportion of Σ3 boundaries tends to decrease and then increase with the increase of dynamic recrystallization (DRX) grain volume fraction, indicating that the presence of twins has a facilitating effect on the nucleation of DRX. In addition, discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) coexist during hot deformation, and DDRX is the main nucleation mechanism. CDRX is easy to occur at middle strain, and its nucleation mode is subgrain rotation nucleation. And there are two types of nucleation for DDRX: grain boundary bulging nucleation and twin‐assisted nucleation.This article is protected by copyright. All rights reserved.

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