Dynamic Mechanical Properties and Modified Johnson-Cook Model Considering Recrystallization Softening for...

Area of Science:

• Materials Science
• Mechanical Engineering
• Metallurgy

Background:

• High-temperature, high-strain-rate deformation during machining can induce dynamic recrystallization in superalloys.
• This recrystallization alters the material's dynamic mechanical properties, complicating machining process analysis.
• Existing models may not fully capture these complex behaviors in nickel-based powder metallurgy superalloys.

Purpose of the Study:

• To propose a modified Johnson-Cook (J-C) model for nickel-based powder metallurgy superalloys.
• To incorporate the effects of dynamic recrystallization under high strain rate and temperature conditions.
• To accurately predict the material's dynamic mechanical properties during machining.

Main Methods:

• Experimental determination of dynamic mechanical properties using quasi-static compression and split Hopkinson pressure bar (SHPB) tests.
• Development of a modified J-C model accounting for dynamic recrystallization.
• Calibration of model coefficients using linear regression analysis.

Main Results:

• The modified J-C model accurately describes the mechanical behavior of nickel-based powder metallurgy superalloys at high strain rates and temperatures.
• Model predictions show good agreement with experimental data.
• The model effectively captures the influence of dynamic recrystallization on material properties.

Conclusions:

• The proposed modified J-C model provides a reliable tool for analyzing nickel-based superalloy machining.
• This research aids in understanding cutting mechanisms and performing finite element simulations.
• Accurate material property prediction is crucial for optimizing machining processes for advanced superalloys.