Microstructural Evolution and Regulation of Inhomogenized 7050 Aluminum Alloy during Compression at Low Temperature

This study investigates the microstructure evolution of inhomogenized 7050 aluminum alloy through hot compression tests performed on the Gleeble−3800 thermal simulation machine. The effects of deformation temperature, strain rate, and height reduction on the microstructure are studied using various analytical techniques including optical microscopy, electron backscatter diffraction (EBSD), and transmission electron microscopy. The results reveal that an increase in temperature enhances dynamic recovery and leads to an increase and subsequent decrease in the content of low-angle boundary (LAB) with a maximum value observed at 200 °C. Furthermore, the ratio and conversion amount of LAB decrease with a decrease in strain rate. The static recrystallization (SRX) is found to be strongly influenced by height reduction, and a 20% height reduction ensures complete SRX without grain growth. In order to evaluate the homogeneity of the microstructure, a coefficient (K) is introduced, and a novel method of microstructure homogeneity regulation is proposed based on both microstructure morphology characteristics and the coefficient (K). The study finds that microstructure homogeneity can be efficiently regulated by cumulative deformation of 20% height reduction and solution treatment in combination, with a deformation temperature of 200 °C at a strain rate of 1 s -1 . Graphical Abstract