Ti matrix composite

For this reason, considered at present are possibilities of creating essentially more cheap materials, namely discontinuously reinforced Ti-matrix composites - so called DRTi. According to Miracle [20], the reinforcement with TiB fibres is the most effective one. For example, incorporation of reinforced phase up to 40 vol. % allows a combination of properties (especially stiffness) to be essentially increased. 

The low cost route, using powder metallurgy for a Ti matrix composite has been recorded [134]. 

OTMC orthorhomic Ti-matrix composites RSP RSS rapid solidification processing resolved shear stress... 

Metal-Matrix Composites. A metal-matrix composite (MMC) is comprised of a metal ahoy, less than 50% by volume that is reinforced by one or more constituents with a significantly higher elastic modulus. Reinforcement materials include carbides, oxides, graphite, borides, intermetahics or even polymeric products. These materials can be used in the form of whiskers, continuous or discontinuous fibers, or particles. Matrices can be made from metal ahoys of Mg, Al, Ti, Cu, Ni or Fe. In addition, intermetahic compounds such as titanium and nickel aluminides, Ti Al and Ni Al, respectively, are also used as a matrix material (58,59). P/M MMC can be formed by a variety of full-density hot consolidation processes, including hot pressing, hot isostatic pressing, extmsion, or forging. 

Fig. 7.22. Riulial cracking in a SiC (ibcr/Ti 24AI 1 INb matrix composite (a) after fabrication ami (b) after additional 1000 thermal cycles. After Arnold et al. (1992).

Finally, metallic fibers find some limited applications as reinforcement in composites. They are generally not desirable due to their inherently high densities and because they present difficulties in coupling to the matrix. Nonetheless, tungsten fibers are used in metal-matrix composites, as are steel fibers in cement composites. There is increasing interest in shape memory alloy filaments, such as Ti-Ni (Nitanol) for use in piezoelectric composites. We will discuss shape-memory alloys and nonstructural composites in later chapters of the text. 

Key words structural efficiency metal matrix composite amorphous metals, superhigh strength Al, nanocrystalline metals, Ti-B alloys... 

The incipient temperature of sharp softening is defined by a titanium matrix composition in full and can be increased by rational alloying from 500°C for the binary Ti-B alloy to 650°C. 

The decrease of the yield stress of the composite with increasing temperature is strongly influenced by dominant softening mechanisms of the titanium matrix phase. At 1000 °C, where conventional titanium alloys are loosing completely their strength, a considerable flow stress of 150 MPa of the a -Ti-Ti5Si3 composite was determined. 

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