Work

Post-dynamic recrystallization in a Ni-based Waspaloy under non-isothermal sub-solvus thermomechanical processing

Year: 2025

Type: article

Abstract: This study investigates the post-dynamic recrystallization (PDRX) behavior of the nickel-based superalloy Waspaloy under sub-solvus conditions. We demonstrate that the conventional direct heating deformation method significantly underestimates the material's microstructural evolution potential, as it fails to replicate the cooling history of actual industrial hot forming processes. To address this, two thermomechanical paths were designed: direct heating deformation and an innovative step-cooling deformation. Remarkably, the step-cooling path promoted extensive PDRX, yielding a uniform fine-grained microstructure. In contrast, PDRX was strongly suppressed in the direct heating specimens. Microstructural analysis indicates that during direct heating, dynamic recrystallization dissolves γ′ precipitates within recrystallized grains, creating a heterogeneous structure where γ′-rich deformed grains exerted a strong pinning force that halted further PDRX. The step-cooling path, by maintaining a ∼50 °C window between γ′ precipitation and dissolution, enabled rapid PDRX in a γ′-free matrix. This work highlights that accurately replicating the industrial thermal history is critical for evaluating the microstructure evolution of phase-transforming superalloys. The step-cooling method provides a more scientifically valid approach compared to conventional direct heating.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2025.12.198

Authors: Chuan Wang, Rui Zhong, Yue Liu, He Jiang, Jianxin Dong

Institution: University of Science and Technology Beijing

Language: English

Topic: Metallurgy and Material Forming

Subfield: Mechanics of Materials

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,640

Funder: National Science and Technology Major Project