Comparison of the phenomenological and physically-based constitutive material equations for GH4033 superalloy

Phenomenological and physically-based constitutive equations for predicting the hot flow stress of the GH4033 superalloy were developed and compared. Isothermal uniaxial compression tests were conducted in the deformation temperatures of 950, 1050, 1150 and 1200 °C, and strain rates of 0.001, 0.01, 0.1, 1, and 10 s⁻¹. Based on the flow stress-strain curves data, phenomenological constitutive equations (modified Johnson-Cook model, Arrhenius-type model) and physically-based constitutive equations (modified Zerilli-Armstrong model, microstructural based model) were developed. The modified Johnson-Cook model and microstructural based model were further modified to enhance the prediction accuracy. The prediction accuracy of the proposed constitutive equations was appraised by the determination coefficient and the average absolute relative error, which are 0.9680 and 14.05 % for the modified Johnson-Cook model, 0.9773 and 9.58 % for the strain compensated Arrhenius-type model, 0.9961 and 6.53 % for the modified Zerilli-Armstrong model and 0.9948 and 4.53 % for the microstructural based model, respectively. The result shows that the proposed physically-based constitutive equations are very suitable for accurately predicting the hot flow stress behavior of GH4033 superalloy.