Hot Deformation Behavior and Microstructure Evolution of a Fe-Ni-Cr Based Superalloy

Area of Science:

• Materials Science
• Metallurgy
• Mechanical Engineering

Background:

• GH2787 superalloy is critical in high-temperature applications.
• Understanding its hot deformation behavior is essential for manufacturing.
• Existing data on its hot working parameters requires systematic investigation.

Purpose of the Study:

• To systematically investigate the hot deformation mechanisms of GH2787 superalloy.
• To develop a predictive model for its flow behavior under hot working conditions.
• To construct a hot working map and identify optimal processing parameters.

Main Methods:

• Hot compression tests were conducted across a temperature range of 1060-1120 °C and strain rates of 0.1-10 s⁻¹.
• An Arrhenius-type constitutive equation was employed to model flow behavior.
• A dynamic material model was used to construct the hot working map.
• Microstructural analysis was performed to examine recrystallization phenomena.

Main Results:

• An accurate Arrhenius-type constitutive equation was developed, with a calculated activation energy (Q) of 364,401.19 J/mol.
• Two preferred processing regions with power dissipation efficiency > 0.3 were identified on the hot working map, with no flow instability observed.
• Dynamic recrystallization (DRX) extent increased with temperature and strain rate, dominated by discontinuous DRX (grain boundary bulging nucleation) and aided by continuous DRX (subgrain rotation and coalescence).

Conclusions:

• The study provides a comprehensive understanding of GH2787 superalloy's hot deformation behavior.
• Optimal processing parameters and regions for hot working were identified.
• The findings offer crucial theoretical guidance for enhancing the manufacturing processes of GH2787 superalloy.