HYBRID EFFECT ON TENSILE PROPERTIES OF IN SITU TITANIUMMATIRX COMPOSITES REINFORCED BY TiBw AND TiCp

摘要

In order to study the in situ hybrid effect of TiBw and TiCp on the tensile properties of titaniummatrix composites, graphite powder was introduced into a Ti-B4C system so that the compositeswith various TiBw/TiCp volume ratios of 4:1, 1:1 and 1:4 were prepared by reactive hot pressingof Ti-B4C-C systems. Room tensile testing results exhibited that the composite with TiBw/TiCpvolume ratio of 1:1 experienced an increase in the ultimate tensile strength of 25% and 50%respectively over that of the composite based on Ti-B4C system and that of pure Ti. The hybridstrengthening effect still existed at elevated temperature, but it was not as obvious as that ofroom-temperature. Meanwhile, the ductility of the composites was decreased with increasingTiCp content. The results suggest that the in situ hybrid effect should be taken into account and anoptimal volume ratio of TiBw/TiCp could provide composites with ideal mechanical properties.