A deformation mechanism map
is a way of representing the dominant deformation mechanism
in a material
loaded under a given set of conditions and thereby its likely failure mode. Deformation mechanism maps consist of some kind of stress plotted
against some kind of temperature axis, typically stress normalised using the shear modulus
versus homologous temperature
. For a given set of operating conditions calculations are undergone and experiments performed to determine the predominant mechanism operative for a given material.
Constructing the Map
Repeated experiments are performed to characterize the mechanism by which the material deforms. The dominant mechanism is the one by which the material will fail, however at any given level of stress and temperature, more than one of the creep
mechanisms may be active. It is left to scientific experiment to determine which controls the failure of the material.
Reading the Map
For a given stress profile and temperature, the point lies in a particular "deformation field". If the values place the point near the center of a field, it is likely that the primary mechanism by which the material will fail, i.e.: the type and rate of failure expected, grain boundary diffusion, plasticity, nabarro-herring creep, etc... If however, the stress and temperature conditions place the point near the boundary between two deformation mechanism regions then the dominating mechanism... Read More