Carbon tensile behavior

Figure 19. Tensile behavior of carbon fibers, based on polyacrylonitrile (PAN) or mesophase pitch (MPP), and compared with polyaramide and glass fibers (48).

Globally, carbon nanotubes have a positive effect on the mechanical properties of all the composites with PVA matrices described in the previous sections. However, the enhancement of mechanical properties differs substantially from a material to another, depending on the type of nanotubes, or on the process used to manufacture the composite. The Young s modulus and the strength are deduced from usual tensile experiments. As depicted in Figure 11.4, PVA/nanotube composites generally follow the same tensile behavior, with a short elastic regime on the first percent strain, followed by a more or less extended plastic behavior. 

FIGURE 12.11 Improvements of the mechanical properties of three-dimensional reinforced CMCs by hybrid infiltration routes (a) R.T. flexural stress-strain plots for a three-dimensional carbon fiber reinforced composite before and after cycles of infiltration (comparison between eight cycles with zirconium propoxide and fonr cycles pins a last infiltration with aluminum-silicon ester (b) plot of the mechanical strength as a fnnction of the final open porosity for composites and matrix of equivalent porosity, before and after infiltration (Reprinted from Colomban, R and Wey, M., Sol-gel control of the matrix net-shape sintering in 3D reinforced ceramic matrix composites, J. Eur. Ceram. Soc., 17, 1475, 1997. With permission from Elsevier) (c) R.T. tensile behavior (d) comparison of the R.T. mechanical strength after thermal treatments at various temperatures. (Reprinted from Colomban, R, Tailoring of the nano/microstructure of heterogeneous ceramics by sol-gel routes, Ceram. Trans., 95, 243, 1998. With permission from The American Ceramic Society.)... 

Bogdanovich AE, Karahan M, Lomov SV, Verpoest I. Quasi-static tensile behavior and progressive damage in carbon/epoxy composite reinforced with 3D non-crimp orthogonal woven fabric. Mech Mater 2013 62 14-31. 

Tserpes, K. I., Panikos, R, Labeas, G., and Panterlakis, S. G. Multi-scale modeling of tensile behavior of carbon nanotube-reinforced composites. Theoret and Appl Fract Mech., 49,51-60(2008). 

Shokrieh, M. M. and Rafiee, R. On the tensile behavior of an embedded carbon nanotube in polymer matrix with non-bonded interphase r ion. J Compos Struct. 2,23-5 (2009). Press Release. US Consulate. World-record-length carbon nanotube grown at US Laboratory. Mumbai-India September 15, (2004). 

Hou, Z., Wang, K., Zhao, R, Zhang, Q., Yang, C., Chen, D. et al. 2008. Structural orientation and tensile behavior in the extrusion-stretched sheets of polypropylene/multi-walled carbon nanotubes composite. Polymer 49 3582-3589. 

The strength and tensile behavior, at room and high temperatures, as well as the structure of three dimensional earbon fiber/SiC composites, fabricated by the slurry pulse/CVI combined process, were eharacterized by Suzuki et al [207-209]. Carbon fiber preforms, constructed with 4-step braid, 4-step/axial braid, 2-step braid and orthogonal weave, were used as reinforcements of the composites. The composites were fabrieated by a process consisting of slurry and dissolved organosilicon polymer infiltrations, followed by the application of pulse CVI. 

Soni et al [269] determined the tensile behavior of carbon fiber reinforced Al matrix composites. The thermal expansion behavior of unidirectional carbon fiber reinforced Cu matrix composites was undertaken by Korb et al [270]. 

A similar trend for a plateau limit in tensile behavior was also described by Jancar and Kucera (13) for calcium carbonate-reinforced composites of polypropylene using maleic anhydride to promote interfacial adhesion. Likewise, they observed convergence of interfacial shear strength value to that of the polypropylene yield strength. 

Zhang M Q, Xu J R, Zhang Z Y, Zeng H M and Xiong X (1996) Effect of transcrystallinity on tensile behavior of discontinuous carbon fiber reinforced semicrystalhne thermoplastic composites. Polymer 37 5151-5158. 

Two different polyacrylonitrile precursor carbon fibers, an A fiber of low tensile modulus and an HM fiber of intermediate tensile modulus were characterized both as to their surface chemical and morphological composition as well as to their behavior in an epoxy matrix under interfacial shear loading conditions. The fiber surfaces were in two conditions. Untreated fibers were used as they were obtained from the reactors and surface treated fibers had a surface oxidative treatment applied to them. Quantitative differences in surface chemistry as well as interfacial shear strength were measur-ed. 

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