Whisker-toughened ceramics

The objective of this task is to expose various structural ceramics to conditions found in smail diesei engines, Commercially available ceramics, as well as new candidate monolithic and whisker-toughened ceramics, will be fabricated Into small MOR bars, nondestructively examined, and exposed to a variety of operating conditions within small diesel engines. Subsequent to exposure, the bars will be nondestructively and destructively examined and the results compared to an unexposed data base. 

Campbell, G.H., Rtihle, M., Dagleish, B.J. and Evans, A.G. Whiskers toughening a comparison between aluminium oxide and silicon nitride toughened with silicon carbide , J. Am. Ceram. Soc., 73[3] (1990) 521-530. 

Briggs, A. and Davidge, R.W., in Whisker-and Fibre-toughened Ceramics, ASM International, Materials Park, OH, p. 153 (1988). 

N. Claussen and G. Petzow, Whisker-Reinforced Zirconia-Toughened Ceramics , in Tailoring Multiphase and Composite Ceramics, eds. R. E. 

M. C. Shaw and K. T. Faber, Temperature-Dependent Toughening in Whisker-Reinforced Ceramics, in Ceramic Microstructures 86 Role of Interfaces, Vol. 21, Materials Science Research Series, Plenum Press, New York, NY, 1987, pp. 929-938. 

R. T. Bhatt, The Properties of Silicon Carbide Fiber-Reinforced Silicon Nitride Composites , in Whisker- and Fiber-Toughened Ceramics, eds. R. A. Bradley, D. E. Clark, D. C. Larsen, and J. O. Stiegler, ASM, Materials Park, PA, 1988, p. 199. 

E. Fitzer, in Whisker- and Fiber-Toughened Ceramics Ceramic and Coated Carbon Fibers for High Temperature Ceramics, ASM International, 1988, pp. 9-52. 

C. A. Anderson, P. Barron-Antolin, A. S. Fareed, and G. H. Schiroky, in Proc. Int. Conf. Whisker and Fiber Toughened Ceramics, American Society for Metals, 1988, pp. 209-215. 

As mentioned before, the development of SiC whisker reinforced alumina was promoted because the mechanical property improvements observed with the incorporation of SiC whiskers into ceramic matrices were unprecedented. For example, the fiacture toughness of alumina was increased from 3.0 MPaVm to 8.5 MPaVm with the addition of 20 v/o whiskers. The increases in toughness for various whisker contents are shown in Fig. 7. The data is summarized from a number of reported studies and so reflect some of the variations in raw materials and processing methods. The results also reflect the maximum toughening... 

N. Claussen and G. Petzow, Whisker-Reinforced Zirconia-Toughened Ceramics pp. 649-62 in Tailoring Multiphase and Composite Ceramics, Vol 20. Edited by R. E. Tiessler, G. L. Messing, C. G. Pantano, and R. E. Newnham. Plenum Press, New Yoik, 1986. 

Fitzer E, Ceramic and coated carbon fibres for high temperature ceramics, Bradley RA, Clark DE, Larsen DC, Stiegler JO eds., ASM International Oak Ridge National Laboratory, Whisker and Fiber Toughened Ceramics, ASM International Oak Ridge National Laboratory, Tennessee, Proc Int Conf, 9-52, Jun 7-9 1988. 

H. Campbell, M. Rilhle, B. J. Dalgleish and A. G, Evans, "Whisker Toughening A Comparison Between Aluminum Oxide and Silicon Nitride Toughened with Silicon Carbide," J. Am. Ceram. Sac., 73 [3] 521-30 (1990). 

The purpose of this research 1s to understand the room temperature and high temperature [1370°C (2500 F)] behavior of toughened ceramics, In particular SIC-whIsker toughened SI3N4, as the basis for developing a life prediction methodology. A major objective Is to understand the relationship between microstructure and the mechanical behavior within the bounds of a limited number of materials. A second major objective is to determine the behavior as a function of time and temperature. 

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 effect of SiC whisker content on toughness enhancement in different matrices. (From P. Becher, Microstructural design of toughened ceramics, /. Am. Ceram. Soc., 74,255-269,1991.)... 

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