Advanced powder-metallurgy technology has led to the development of the CermeTi ® family of titanium metalmatrix composites. Reinforcing the titanium alloy matrix with titanium carbide or titanium boride particles results in superior properties. These discontinuously reinforced titanium composites have excellent room-and elevated-temperature properties and are exceptionally wear resistant. High quality, near-net shape CermeTi composite components are being produced commercially and are being evaluated for potential applications in military vehicles, commercial automotive engines, sporting goods, industrial tooling, and biomedical devices.

Tungsten-reinforced Ti and Ti Á/6Al Á/4V composites were fabricated by powder metallurgical techniques from Ti, W and Al Á/V powders. The microstructure of the composites consists of partially dissolved tungsten particles within an a/b titanium matrix containing tungsten in solid-solution. Yield and ultimate tensile strengths increase linearly with tungsten content in the range 0 Á/15 wt.% W and decrease near-linearly with temperature in the range 25 Á/540 8C. Ductility follows the opposite trend and is within technologically acceptable values, except for Ti/15W at 315 and 425 8C and Ti/10W at 540 8C which fractured near the ultimate stress value. The Ti Á/6Al Á/4V/10W composite shows the best combination of high strength and ductility at all temperatures. At ambient temperatures, Ti/10W exhibits a stress Á/strain curve very similar to Ti Á/6Al Á/4V (with a slight decrease in stiffness), while eliminating aluminum and vanadium alloy elements. Further improvements in mechanical properties of these non-equilibrium composites are likely to be achieved through optimized heat-treatments, which affect the matrix microstructure and the degree of dissolution of tungsten and thus the relative importance of matrix solid-solution strengthening and composite strengthening. # 2002 Published by Elsevier Science B.V.

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Advanced powder-metallurgy (P 1M) technology provides the key to a new class of low-CX)St,high-performance titanium-matrix composites known as CermeTi. Titanium carbide, the most successful particulate addition to date, imparts both strengthening effects and enhancement of the bulk modulus of elasticity when added to a titanium-alloy matrix. This article describes the process development and properties of these materials and describes the transfer of this technology from its early success in cost-effective defense applications to commercialization in highly competitive applications.

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