MECHANICAL-BEHAVIOR OF DAMAGE-TOLERANT TIB WHISKER-REINFORCED IN-SITUTITANIUM MATRIX COMPOSITES

The results of a systematic study of the effects of alloying and micro structure on the mechanical behavior of in situ titanium matrix compos ites are reported in this paper. In situ composites are produced by al loying with B which promotes the formation of TiB whiskers during rapi d solidification processing. The composite powders are subsequently co mpacted and extruded to align the whiskers prior to systematic heat tr eatment in the beta and/or alpha + beta phase fields. The processing c onditions for the development of in situ composites with attractive co mbinations of strength, ductility, damage tolerance and creep resistan ce are thus established. The improvements in the composite properties are rationalized using simple micromechanics principles. The paper hig hlights the potential for the microstructural design of composites usi ng micromechanics and conventional physical metallurgy principles.