Work

A constitutive model optimizing superalloy performance: The interplay of annealing twins, dislocations, and grain boundaries

Year: 2025

Type: article

Abstract: Heat treatment at different temperatures can effectively enhance the strength of nickel-based superalloys while maintaining good ductility. To gain an in-depth understanding of how heat treatment influences deformation mechanisms during subsequent tensile strain, advanced techniques such as high-precision planar argon ion polishing and electron backscatter diffraction were employed. These methods precisely measured the annealing twin volume fraction, dislocation density, and grain size. Based on these data, a constitutive model coupling annealing twin volume fraction, dislocation density, and grain size was constructed. This model was used to analyze the contributions of various strengthening mechanisms to the tensile flow stress of nickel-based superalloys under different heat treatment conditions, as well as the interactions between annealing twin boundaries (ATBs), dislocations, and grain boundaries during deformation. The results revealed that although dislocation multiplication consistently plays a critical role in determining the maximum flow stress, the effects of annealing twins and grain boundaries on strain hardening become increasingly significant at higher temperatures. Specifically, a high density of annealing twins not only facilitates dislocation multiplication, further enhancing dislocation strengthening, but also demonstrates a crucial relationship between twin spacing and volume fraction in influencing annealing twin strengthening. Furthermore, higher dislocation density accelerates grain refinement and promotes grain boundary strengthening, while a higher annealing twin volume fraction slows this process, thereby limiting the extent of grain boundary strengthening. This study deepens the understanding of how heat treatment influences the deformation mechanisms of nickel-based superalloys and provides theoretical guidance for optimizing heat treatment processes to achieve desirable mechanical properties.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2025.07.014

Authors: Zongpeng Tian, Rui Zhao, Xinshun Diao, Shan Jiang, Debin Shan, Min Wan

Institutions: Beihang University, Aviation Industry Corporation of China (China), AviChina Industry & Technology (China), Harbin Institute of Technology

Language: English

Topic: High Temperature Alloys and Creep

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,640

Funders: Aviation Industry Corporation of China, Key Research and Development Program of Jiangxi Province