Experimental investigation of the hot deformation behavior of AA7075: Development and comparison of flow localization parameter and dynamic material model processing maps

• Processing map of AA7075 is developed based on the flow localization parameter.
• Novel criteria are used to develop more accurate processing map based on DMM.
• The mentioned models and conventional DMM are compared with each other.
• Stable, unstable and most efficient workable regions are determined.
• Occurrences of DSA and DRX were observed and discussed briefly.

The hot deformation characteristics of 7075 aluminum alloy (AA7075) are investigated by means of hot compression tests carried out in the temperature range of 200–450 °C and strain rate range of 0.0003–1 s−1. Two novel processing maps based on flow localization parameter and enhanced DMM are developed and compared with conventional DMM results. It is observed that processing maps based on flow localization parameter can be used successfully to predict AA7075 thermomechanical behavior. Also, the comparison of the DMM results indicates that the new approach to calculate DMM power dissipation efficiency and instability criteria corresponds better with experimental observations. The occurrence of dynamic recrystallization is probable in the temperature range of 400–450 °C and strain rates of lower than 0.001 s−1. Moreover, the alloy demonstrated a wide range of flow instabilities at temperatures lower than 300 °C and all strain rates tested where the occurrence of dynamic strain ageing is suggested at this domain. However, the most efficient temperature range to deform the alloy is suggested as 300–350 °C at strain rates lower than 0.001 s−1.