Influence of extrusion processing variables on the microstructure and mechanical properties of aluminum-lithium alloy extrusions

Extrusion temperature, strain rate, extrusion ratio, biller temperature, and extrusion geometry were varied, and correlated with the microstructure of the alloy, and the heat treating times and temperatures. The extrusion processing variables were related to the microstructure through the Zener-Hollomon parameter i.e., the temperature compensated strain rate. Based on optical and transmission electron microscopy studies it was found that regardless of the extrusion conditions, the various microstructures were for the most part were unrecrystallized for both the as-extruded and the solution heat treated conditions. Smaller grain sizes were correlated to smaller Zenor-Hollomon parameters. The extrusion temperature and ratio did not significantly effect the strength or elongation. The section geometry did effect these mechanical properties.