Dynamic Recrystallization of Al Alloy 7075 in Turning

Abstract

This work investigates the effects of turning process parameters on recrystallization behavior in Al alloy 7075. To realize this purpose, samples were machined under different cutting speeds and material feed rates at two extreme levels. Microscopy imaging reveals that activation of dynamic recrystallization or grain growth depends on the combination of applied cutting parameters. Increasing the cutting speed intensifies recrystallization, while the feed rate governs the grain growth. Adjusting the cutting parameters enables one to obtain a desired average grain size below the machined surface, up to a ∼180 μm depth. The average grain size of the initial material was 31.6 μm. The imposed processing parameters successfully yielded average grain sizes in the range from 19 to 44 μm. Additionally, a computational framework work consisting of finite-element analysis (FEA) coupled with kinetic-based modeling of recrystallization was developed, which is capable of following the trend of change in the average grain size and acceptably predicts the evolved average grain size.