THE ROLE OF INHOMOGENEOUS DEFORMATION IN HIGH-TEMPERATURE RING COMPRESSION TESTING

Elastic-viscoplastic constitutive equations that enable the modelling of rate effects, temperature effects and dynamic recrystallization are employed to model the ring compression test at high temperatures. The effects of strain rate and temperature on the calibration curves, use d widely to characterize frictional behaviour in forging, are investig ated. Both strain rate and temperature are found to influence the cali bration curves obtained, and it is found that the influence derives fr om the dependency of dynamic recrystallization processes on strain rat e and temperature. The coupling between the deformation and the recrys tallization process is found to lead to the establishment of significa ntly different strain fields with different strain rates, and it is th is that leads to the dependency of the calibration curves on strain ra te and temperature. A methodology has been presented for the determina tion of friction calibration curves for hot forging of high-performanc e materials, which accounts for strain rate effects, temperature effec ts and recrystallization processes. The method is likely to be useful to industries involved in the high-temperature processing of high-perf ormance components.