Hot Deformation Behavior and Processing Map of GH901 Superalloy

Rui Ma,Lulu Li,Ruixue Zhai,Jun Zhao,Xiangnan Meng

doi:10.3390/met11111808

Abstract

During the forging process GH901 superalloys easily produce cracks and defects, such as coarse crystals in tissues, which affect the performance of the alloy. Using GH901 nickel-based alloy, high-temperature compression tests at deformation temperatures of 990, 1040, 1090 and 1140 °C were carried out in a Thermecmastor-Z thermal simulator, with strain rates 0.001, 0.01, 0.1 and 1 s−1. Next, the isothermal forging process of a GH901 disc was simulated using DEFORM finite element simulation software. The results showed that with the increase in deformation temperatures and the decrease in strain rates, the flow stress clearly decreased. The flow stress constitutive model of GH901 superalloy under ε0.3 and the flow stress constitutive model for strain compensation were obtained. The processing map was built, and a reasonable range of thermal processing was obtained. Meanwhile, the isothermal forging simulation verified the reliability of the thermal processing range of the alloy.

Highlights

Nickel-based superalloy [1,2] is a kind of superalloy with high strength, good oxidation resistance and gas corrosion resistance in the range of 650–1000 ◦C
The deformation temperatures ranged from 1100 ◦C to 1140 ◦C and the strain rates ranged from 0.001–0.35 s−1
Processing maps of GH901 superalloy based on strain 0.3 and strain compensation were constructed

Summary

Introduction

Nickel-based superalloy [1,2] is a kind of superalloy with high strength, good oxidation resistance and gas corrosion resistance in the range of 650–1000 ◦C. The name derives from the fact that its content is generally more than 50% nickel. The use of this superalloy is widespread across numerous fields, including aerospace, automobile parts manufacturing, and gas hydrate formation. The macroscopic hot deformation behavior of superalloy corresponds with the dynamic recovery and dynamic recrystallization mechanism in the alloy. By formulating different process parameters to capture the experimental data, the true stress–strain curve of the alloy can be obtained. The hot deformation constitutive equation [3,4,5] and processing map of the alloy are obtained by constructing the relationship among deformation temperatures, strain rates and deformation amount. The microstructure and machinability of the alloy under hot deformation can be accurately predicted by analyzing the processing map [6,7,8]

Methods

Results

Conclusion