Fiber orientation during equal channel angular extrusion of short fiber reinforced thermoplastics

Glass-fiber/polyacetal cylindrical rods prepared by conventional compounding and extrusion were processed by equal channel angular extrusion (ECAE). The initial material contained 109.8 mu m long fibers with uniformly distributed fiber angle orientations between 11.8 and 56.0 degrees. One extrusion pass with a soft matrix at 73 degrees C directed the fibers to a loglogistic distribution with a mean orientation angle of 23.5 degrees. ECAE at room temperature did this with mean fiber angles becoming 20.8 and 23.6 degrees for one and two passes respectively. The interquartile range of the angles narrowed with reduced processing temperature and number of processing passes.