A large body of experimental data accumulated in the power-law creep regime over the last several decades has revealed a remarkable similarity in the creep behavior of many materials varying from metals, intermetallics, ionic salts, ceramics to geological materials. Although several creep models have been proposed, they are largely limited in their inability to rationalize many experimental observations. A universal approach to creep modeling is proposed in this paper with a long term objective of impacting engineering design. First, creep microstructural observations are qualitatively rationalized in terms of a bifurcation diagram. Next, the use of nonlinear dislocation dynamics in creep modeling is advocated to rationalize the observed diversity in the creep substructures, and a simple technique for formulating these equations is discussed. A method is proposed for scaling-up the dislocation substructure evolution models by coupling them to a viscoplastic model through the volume fractions of the "hard" and "soft" phases. This coupling is shown to lead to the stress-subgrain size relationship in a simple and mural way.
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