Review: developments in the creep of materials over a period of more than a century

Studies of creep may be traced back for more than 100 years and this extensive experimentation has produced a comprehensive understanding of the various flow mechanisms occurring in the steady-state or secondary stage of creep. These mechanisms range from diffusional creep and Harper-Dorn creep at low stresses to dislocation processes such as glide and climb at higher stresses and to grain boundary sliding where the rate is dependent primarily upon the grain size. This review examines the nature and characteristics of these flow processes and then demonstrates that the theoretical predictions are generally in good agreement with the experimental data. Finally, two examples are presented, in the fields of structural engineering and glaciology, to illustrate the potential for making significant new contributions to the understanding of the creep processes.