Whiskers toughening

Fig. 13. Micromechanics of whisker toughening (a) schematic diagram depicting frictional bridging, whisker fracture and pullout and (b) electron...

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. 

Micromechanical modeling and available experimental evidence indicates that the composite toughness, KIc (composite), can be described as the sum of the matrix toughness, KIc (matrix), and a contribution due to whisker toughening, AKIc (whisker reinforcement).1,23 In other words,... 

Silicon Nitride Matrix SiC-Whisker-Toughened Silicon Nitride... 

Complete analysis of candidate silicon nitride powders and silicon carbide whiskers for fabrication of whisker-toughened silicon nitride composites choose the reference materials for the GTE composite development program. 

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. 

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. 

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