Toughening behavior

Becher, P.F. and Tiegs, T.N. (1987). Toughening behavior involving multiple mechanisms whisker reinforcement and zirconia toughening. J. Am. Ceram. Soc. 70, 651-654. 

Chiu, H.-T. Chiu, W.-M. The toughening behavior in propylene-ethylene block copolymer filled with carbon black and styrene-ethylene butylene-styrene triblock copolymer. Mater. Chem. Phys. 56, 108-115 (1998). 

Research into the toughening behavior responsible in the composite materials shows that crack-whisker interaction resulting in crack bridging, whisker pull-out and crack deflection are the major toughening mechanisms. 

In both derivations of toughening behavior, increases in toughness for whisker-reinforced composites are dependent on the following parameters (1) whisker strength, (2) volume fraction of whiskers, (3) elastic modulus of the composite and whisker, (4) whisker diameter, and (5) interfacial fracture energies. 

P. F. Becher and T. N. Tiegs, Toughening Behavior Involving Multiple Mechanisms Whisker Reinforcement and Zirconia Toughening, J. Am. Ceram., 70[9], 651-654 (1987). 

T. Nose, M. Ueki, T. Fujii, and H. Kubo, Toughening Behavior in SiC Whisker Reinforced A1203 Ceramics, Paper presented at the 1st International Ceramic Science Technology Congress, Oct. 31-Nov. 3, 1989, Anaheim, CA. 

The toughening of PA depends on materials and on structural and test parameters. The toughening behavior at high speeds as a function of temperature gives an S-curve with a discontinuous transition. The materials and structural limit have a shift effect on this S-curve. Deformation occurs first by cavitation of the rubber, and then by plastic deformation of the cavitated ma-... 

Polyethylene Terephthalate Blends Wilfong et al. [1986] reported on the effects of blending low concentrations (1 to 10 wt%) polyolefin with PET on the crystallization and toughening behavior of the latter. The authors... 

As can be deduced from the discussion above, the characteristics of the whiskers, such as diameter and strength, have a direct effect on the toughening behavior and mechanical behavior, The surface chemistry of the whiskers influences the nature of the interface bond between the whiskers and the matrix, which is addressed in the y /y/ term in Eq. 2. It has been found that whiskers from various manufacturers have different characteristics, which affect their performance as reinforcements. 

A general summary of typical physical characteristics of selected SiC whiskers is given in Table 1. The performance of the whiskers in a number of applications is dependent in part on the diameter and aspect ratio. For example, the toughening behavior in alumina matrix composites is dependent on the ability of the whiskers to bridge propagating cracks. This... 

In contrast, Li and Shimizu [103] ascribed the toughening behavior of the PLA-based blends to debonding at the rubber/matrix interface during deformation, which released the hydrostatic stress and facilitated the occurrence of shear yielding. When the hydrostatic stress is released within a PLA/polyurethane elastomer (PU) blend, debonding is easily induced at the interface between the (PU) domains and PLA matrix. This results in voids around the rubber, which allows shear yielding and improved the toughness of the materials, as shown by... 

Wilfong et al. (1986) reported on the effects of blending low concentrations (1-10 wt%) polyolefin with PET on the crystallization and toughening behavior of the latter. The authors studied blends of PET with LLDPE, HDPE, PP, and poly (4-methylpentene-l), all of them having a lower melting point than PET (Table 3.15). Polyolefin melts did not enhance the nucleation of PET, although the spherulite size of the PET matrix was found to be 2.5-3 times larger than for the homopolymer, with a broader spherulite size distribution. Both the crystallization... 

Becher, P. F., Heueh, C., Angellita, P., and Tiegs, T. N. (1988). Toughening behavior in whisker-reinforced ceramic matrix composites. / Am. Ceram Soc. 71 1051-1061. Homeny,J., Vaughn, W. L., and Ferber, M. K. (1990). Silicon carbide whisker/alumina matrix composites effect of whisker surface treatment on fracture toughness./ Am Ceram. Soc. 73 394-402. 

The research works on toughening mechanisms and fracture toughness of ceramic composites with piezoelectric phases have been limited, while those for monolithic piezoelectric/ferroelectric materials have been available, as mentioned above. Therefore, details of toughening behavior and mechanisms in composite materials with piezoelectric phases have been still not clear. 

Nawa, M., Yamada, K. and Pezzotti, G. (2008) Miaoscopic mechanisms behind the toughening behavior of ceria stabilized tetragonal zirconia/alumina nanocomposite for biomedical applications. Key Engineering Materials, 361-363, 813-16. 

Dompas D, Groeninckx G (1994) Toughening behavior of rubber-modified thermoplastic polymers involving very small rubber partides. 1. A criterion for internal rubber cavitation. Polymer 35 4743... 

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