Creep behavior of Si₃N₄-whisker-reinforced Si₃N₄-matrix composites using an in situ dynamic beam profiling method

A four-point flexure test, capable of simultaneously measuring load-point and beam-center displacements and permitting in situ profiling of the beam throughout the test, has been developed. Compressive and tensile strains in the outer fibers, together with the neutral axis displacement, were determined in real time for Si₃N₄-whisker-reinforced Si₃N₄-ceramic-matrix composites. Combining these data with the closed form solution of Chen and Chuang gave excellent correspondence between the creep exponents determined from flexure tests with those determined independently from tensile and compressive creep tests.