Micromechanical modelling of creep using distributed parameters

✍ Scribed by Rishi Raj; A.K. Ghosh

• Publisher: Elsevier Science
• Year: 1981
• Weight: 853 KB
• Volume: 29
• Category: Article
• ISSN: 0001-6160
• DOI: 10.1016/0001-6160(81)90155-3

✦ Synopsis

Abstrnct-Microstructural

parameters such as diffusion coefficients and grain size usually have distributed vaiues in a polycrynal. However. micromechanical constitutive equations for power-law creep and diffusional creep assume that these parameters are uniform. In this paper it is shown that the use of distributed parameters can lead to a transition from power-law creep to diffusional creep which is spread over several orders of magnitude in strain rate. It also leads to the generation of internal stress and anelasticity. Two specific cases, a bimodal distribution of grain size and a fwo phase structure. are anaiysed in detail. A graphical analytical technique which is developed can be extended to other distribution functions; but even the simple bimodal structures are relevant to engineering materials such as austcnitic stainless steels and m-8 titanium alloys. This paper primarily concerns steady state creep and includes a brief discussion on the transient problem. Further developments will be given in a subsequent paper.