Dynamic mechanical properties of FGH4097 powder alloy and the applications of its constitutive model

Abstract

As a typical multiphase alloy, FGH4097 has good lasting strength (thermal stability and thermal fatigue properties), excellent wear resistance and heat resistance. It has been widely used in aerospace and other hot-end parts manufacturing fields. Most of the existing researches on the mechanical properties of FGH4097 alloy are carried out at low strain rate. There is no effective research on high temperature dynamic mechanical properties of FGH4097. Through the impact compression test of FGH4097 under different strain rates and different temperature conditions by the split Hopkinson compression bar equipment, the corresponding true stress-true strain curve was obtained, the strain rate sensitivity and temperature sensitivity of the material were analyzed. The specific heat capacity of FGH4097 alloy at different temperatures was measured by a laser thermal conductivity meter, and the adiabatic temperature rise of the alloy at different temperatures and strain rates was studied. The isothermal true stress-strain curve of the alloy was obtained by calculating the thermal softening coefficient. Two constitutive equations, Johnson-Cook and Power-Law, were introduced to fit and characterize the dynamic mechanical properties of FGH4097 alloy at different strain rates and temperatures, and the corresponding material constitutive models were obtained. Comparing the fitting accuracy of the two models, it is found that the fitting accuracy of the Power-Law model is higher, with an average error of less than 8%. The cutting simulation of FGH4097 alloy was carried out by AdvantEdge software, and the effects of strain and strain rate on the machinability of FGH4097 alloy were investigated.

Keywords

• FGH4097
• Dynamic mechanical properties
• Adiabatic temperature rise
• Power-law model
• Johnson-cook model
• Cutting simulation