Réduction des coûts de fabrication des composites "in-srtu" Ti/TiB et Ti-6AI-4V/TiB

New anisotropic titanium composites reinforced by continuous SiC fibres deposited by CVD were developed a far years ago and are now on the market but they are still very expensive when compared to other Metallic Matrix Composites (MMC and conventional titanium alloys. With a view to cutting the cost of these composites, the study reported here was aimed at achieving reinforcement (TiB) directly during the preparation of the composite itself. The resulting composite material can therefore be called "in-situ" composites. This article analyses the mcrostructure and mechanical properties of composites cast in a precision foundry. The composites produced by this process have a very fine microstructure that delivers a very interesting combination of mechanical properties. Increating the volume fraction of reinforcement improves the ultimate tensile strength and the Young's modulus. On the other hand, the higher the TiB level, the lower the ductylity. A volume fraction compromise must be found to attain a satisfactory mechanial strength and ductility at ambient temperature. At higher temperatures (300-400°C, the mechanical strength is even greater when compared to alloys with an unreinforced matrix.