Normalization of hot deformation parameters for activation energy analysis in metallic alloys

Depending on the melting point of a given alloy, the temperature range for hot deformation of alloys varies widely. Consequently, the apparent activation energy of hot deformation, Q, is greatly influenced by the temperature range as well as the strain rate applied during hot deformation. The purpose of this investigation is to normalize hot deformation parameters-temperature and strain rate-to study their effects on activation energy. Seventy published hot-deformation datasets were used to investigate the effects of normalized hot-deformation variables on Arrhenius-type constitutive model parameters. Flow stress, strain rate, and temperature from sample datasets were normalized to the range [0, 1] and fitted with an Arrhenius-type model. The results showed that, for normalized parameters, the activation energy has exponential relationships with the partial derivative of flow stress with respect to strain rate and temperature.