Determination of Interfacial Shear Stress in Fiber-Reinforced Ceramics by Protrusion Technique

A new “Protrusion” technique, which utilize protrusion behavior after a longitudinal compression test, for the measurement of interfacial shear sliding stress has been developed. The analytical procedure for the calculation of the shear stress from room to elevated temperature was obtained and the model experimental results on single SiC fiber-reinforced borosilicate glass matrix model composite were compared with the theoretical calculation. The results of the model composite indicated that the applied stress versus protruded length showed reasonably good agreement between the measured protruded length and calculated data. The obtained interfacial shear sliding stress showed reasonable agreement with the value measured by another technique. The technique was also applied to the measurement of the interfacial shear stress in SiC fiber-reinforced LAS-II matrix composite to investigate possibility of the technique for engineering composite. The result showed that both the distribution of the shear stress and temperature dependence of them were obtained from one protrusion test. It was concluded that the advantages of the protrusion technique are: i) no need for special equipment, ii) mapping of interfacial shear stress can be obtained, and iii) possible to apply for elevated temperatures without any special equipment. Some discussion on the temperature dependence of measured interfacial shear stresses are presented.