Analysis and constitutive modeling of high strain rate deformation behavior of Haynes 282 aerospace superalloy

Abstract

Haynes 282 is a relatively new γ′- strengthened superalloy used in static and rotating components of jet turbine engines. An understanding of its high strain rate behavior is required to develop constitutive model to predict and optimize its response under dynamic loading applications. Using the direct impact Hopkinson pressure bar, this study investigates the high strain rate behavior of Haynes 282 at strain rates from 2000/s to 10,000/s and temperatures from 25 to 800 °C under three heat treatment conditions (solutionized, standard aged, and special aged). Experimental results show that the flow stress of Haynes 282 remains nearly constant or decreases with increases in strain rate, a remarkable feature that could increase its resistance to impact damage. This contrasts with Inconel 718, the most-widely used superalloy, which show positive strain rate sensitivity. An Arrhenius-type and modified Johnson-Cook constitutive models are developed to predict the combined effects of work hardening, strain rate softening, and temperature on the high strain rate behavior of Haynes 282. The model prediction shows good agreement with the experimental observations. The modified JC model has a higher correlation coefficient and lower average absolute relative error than the Arrhenius-type model, a statistical indication of higher predictability. Nevertheless, both models present powerful tool for designers to simulate and optimize high impact load-bearing applications.