Interface controlled diffusional creep

E. Arzt, M.F. Ashby, and R.A. Verrall. Interface controlled diffusional creep. Acta Metall., 31(12) 1977-1989, 1983. 

Arzt, E., Ashby, M.F., and Verrall, R.A., Interface-controlled diffusional creep , Acta Metal., 1983, 31, 1977-89. 

In this equation, A is a constant, Q is the apparent activation energy, R is the gas constant, G is the shear modulus, and p and n are the inverse grain size and stress exponents, respectively. The values of n and Q, measured for the fibers considered here, are listed in Table VI. The high values of n suggest that creep deformation is rate controlled by an interface reaction-limited grain boundary diffusional process [78], Mullite fibers are more resistant to creep than a-alumina fibers. For example, the strain rate of the Nextel 480 mullite fiber at 1200 C is almost two orders of magnitude lower than that of the Nextel 610 a-alumina fiber [55]. 

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