Titanium matrix

Other than in polymer matrix composites, the chemical reaction between elements of constituents takes place in different ways. Reaction occurs to form a new compound(s) at the interface region in MMCs, particularly those manufactured by a molten metal infiltration process. Reaction involves transfer of atoms from one or both of the constituents to the reaction site near the interface and these transfer processes are diffusion controlled. Depending on the composite constituents, the atoms of the fiber surface diffuse through the reaction site, (for example, in the boron fiber-titanium matrix system, this causes a significant volume contraction due to void formation in the center of the fiber or at the fiber-compound interface (Blackburn et al., 1966)), or the matrix atoms diffuse through the reaction product. Continued reaction to form a new compound at the interface region is generally harmful to the mechanical properties of composites. 

James, N.A., Lovett, D.J. and Warwick, C.M. (1991). Mechanical behavior of a continuous fiber reinforced titanium matrix composites. In Proc. ICCMjS. Composites Design, Manufacture and Application (S.W. Tsai and G.S. Springer, eds.), SAMPE Pub., paper 191. 

Martineau P., Pailler, R., Lahaye, M. and Naslain, R. (1984). SiC filament/titanium matrix composites regarded as model composites, part 11, J. Mater. Sci. 19, 2749-2770. 

Another challenge faced by sol-gel technologies involves controUing the dispersion of different metals within a mixed metal (e.g., sihcon and titanium) matrix. The solvolysis and condensation steps for metal alkoxide precursors involved in sol-gel reactions can be quite different from that of orthosilicates, which often leads to the loss of dispersion and formation of separate silica and other metal oxide domains [54]. 

System Ti-B-X represents a basis for development of alloys with a high stiffness, especially at additional alloying with aluminum [24], Titanium boride has high Young modulus and simultaneously it is practically insoluble in titanium matrix. Aluminum is one of few elements, which being dissolved in titanium increases Young modulus of matrix. 

It is necessary to note that both borides and silicides in the investigated systems exhibit a good cohesion with titanium matrix. In particular, it is practically never revealed on fracture surfaces of these alloys any lamination of particles of the strengthening phase from matrix. 

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. 

In order to take advantage of the superior properties of these refractory silicides in combination with a ductile titanium matrix particle and fiber reinforced composites based on a-Ti-Si-(Al) have been developed. Two different processing routes have been performed ... 

Despite the fact that the reinforcing Ti5Si3 fibers are not continuously aligned within the a-titanium matrix the rule of mixture can be applied because the aspect ratio 11 /dF = 50 is fairly high and sufficient enough to transfer the load from the solid solution strengthened matrix to the fibers [25]. Assuming that the solid solution a-Ti(Si) matrix has a flow stress of about om = Em = 300 MPa at room temperature, the effective flow stress of the... 

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. 

The unidirectionally solidified Ti-Ti5Si eutectic behaves more ductile and the stress intensity factor exhibits a strong increase up to 500 °C and higher. No ductile-to-brittle transition occurs below room temperature. This behavior is caused by the sufficient ductility of the a-titanium matrix. 

Ways to increase membrane durability have been examined by various researchers across the country. Maurtiz et al. examined the use of metal-oxide metal particles to increase the properties of the membrane. A titanium isopropoxide (Figure 11.4) addition to Nation membranes generates quasi-network particles this improves membrane modulus and dimensional stability [17], In addition, the titanium matrix reduces fuel crossover and minimizes chemical degradation. Table 11.2 shows the increase in modulus along with stress and strain and stress changes after the addition of the titanium matrix [17], With a 20% load of the titanium matrix, performance criteria remain comparable. Acid functionality remains intact however, water uptake is reduced as volume inside clusters is occupied. Conductivity is reduced due to chain mobility [17],... 

TDT thermal decomposition tempera- TMC titanium-matrix composite... 

P. Rangaswamy, M.A.M. Bourke, P.K. Wright. N. Jayaraman, . Kartzmark, J.A. Roberts, The influence of thermal-mechanical processing on residual stresses in titanium matrix composites, Materials Science Engineering A, 224, 200-209, (1997). 

Low cost PM route for titanium matrix carbon fiber composites. Powder Metall, 39(2), 97 99, 1996. 

Electrolytic Production of Matrix Coated Fibres for Titanium Matrix Composites... 

Leyens, C., Hausmann, J., and Kumpfert, J. (2003) Continuous fiber reinforced titanium matrix composites fabrication, properties, and applications. A4v. Eng. Mater., 5(6), 399-410. 

Mail, S. and Nicholas, T. (eds) (1998) Titanium Matrix Composites, Technomic Publishing Co., Lancester. 

Sanguinetti Ferreira, R.A., Arvieu, C., Guillaume, B., and Quenisset, J.M. (2006) Titanium matrix composites processed by continuous binder-powder coating an alternative fabrication route. Compos. Part A Appl. Sci. Manuf., 37(10), 1831-1836. 

The kinetics of phase transformation and wear resistance of in-situ processed titanium matrix composites based on B-Fe-Ti has been studied by [1999Bra]. The sintering parameters employed when using the powder metallurgical route were improved with the aim of increasing wear resistance. 

Bra] Bram, M., Aubertin, F., Venskutonis, A., Breme, L, Kinetics of the Phase Transformation and Wear Resistance of In-situ Processed Titanium Matrix Composites Based on Ti-Fe-B , Mater. Scl Eng. A, 264(1-2), 74-80 (1999) (Morphology, Phase Relations, Thermodyn., Experimental, Kinetics, 20)... 

Oxidation of fibre-reinforced titanium matrix composites... 

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