Creep of crystalline materials: experimental basis, mechanisms and models

Creep tests, in the general sense of deformation testing under stress control, are a simple, but powerful and unique means of studying the work hardening and the deformation kinetics of materials. Simple material-independent constitutive relations with dimensionless parameters are available to estimate the dependence of creep resistance and dislocation structure on stress for single-phase materials. The microstructural mechanisms relevant to creep are briefly reviewed. Insufficient understanding of particle hardening and, most importantly, the group of dislocation processes involved in dynamic dislocation recovery appear to be the limiting factors in modelling creep.