Recent Advances in Development of High Performance Composites

Abstract

Considerable progress has been made in development of reinforcing agents which combine high strength and stiffness with low density and good thermal resistance. Status of work carried out on the use of single crystal whiskers, polycrystalline fibers and single crystal flakes as reinforcing materials is dis cussed. Progress made on incorporating these various types of reinforcing agents into composites is reviewed. Whiskers are shown to have considerable potential but because of subcriti cal length and low strength poor translation of properties has been reported. Continuous filaments of boron and graphite ap pear to provide the most immediate opportunity for develop ment of high performance composites. However, eventually it appears that single crystal flakes will provide the greatest advantage because of their tendency to reinforce in the planar direction. For high temperature application composites rein forced with boron nitride or carbon fiber are the most promising.