INFLUENCE OF FIBER ASPECT RATIO ON THE STRESS-RUPTURE LIFE OF DISCONTINUOUS FIBER COMPOSITES

摘要

An investigation of the effect of critical aspect ratio on the stress-rupture life of discon¬tinuous fiber reinforced composites was carried out. Pull-out specimens of tungsten wire and copper were tested at 1200° and 1500° F (649° and 816° C) for nominal stress-rupture times of 1, 10, and 100 hr. The observed critical aspect ratios were greater than in short-time tensile tests but were within the same order of magnitude at tempera¬tures as high as 1500° F (816° C). Failure time of the specimens was controlled by the properties of the matrix (copper) at ratios less than the critical aspect ratio and by the properties of the fiber (tungsten) at aspect ratios greater than the critical aspect ratio.