Extrusion-Machining as an Analog to Investigate the Deformation Zone Mechanics during the Aluminum Extrusion Process

摘要

Extrusion-machining combines cutting with simultaneous extrusion using an additional constraining tool to induce very large and well-characterized effective strains. Unlike conventional extrusion, accurate analytical models exist for the extrusion-machining process to calculate values of effective strain, strain rate, and temperature rise in the deformation zone as a function of processing parameters. The extmsion-machining process is therefore useful as an analog to explore the deformation mechanics of conventional aluminum extrusion experimentally, as local processing conditions are otherwise impossible to measure. This process is used in conjunction with finite element models to investigate the effects of individual variables on the material response of 6xxx-series and 7xxx-series aluminum alloys during the conventional extrusion process. Results of this work are shedding light on the microstructural evolution seen during extrusion, specifically relating to the surface recrystallization that causes the peripheral coarse grain defect.