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

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 degrees 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 degrees 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 degrees 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 degrees C at strain rates lower than 0.001 s(-1). (C) 2013 Elsevier Ltd. All rights reserved.