text: A deformation mechanism map is a way of representing the dominant deformation mechanism in a material loaded under a given set of conditions. The technique is applicable to all crystalline materials, metallurgical as well as geological. Additionally, work has been conducted regarding the use of deformation maps to nanostructured or very fine grain materials. Deformation mechanism maps usually consist of some kind of stress plotted against some kind of temperature axis, typically stress normalized using the shear modulus versus homologous temperature with contours of strain rate. The normalized shear stress is plotted on a log scale. While plots of normalized shear stress vs. homologous temperature are most common, other forms of deformation mechanism maps include shear strain rate vs. normalized shear stress and shear strain rate vs. homologous temperature. Thus deformation maps can be constructed using any two of stress (normalized), temperature (normalized), and strain rate, with contours of the third variable. A stress/strain rate plot is useful because power-law mechanisms then have contours of temperature which are straight lines.
  For a given set of operating conditions, calculations are conducted and experiments performed to determine the predominant mechanism operative for a given material.  Constitutive equations for the type of mechanism have been developed for each deformation mechanism and are used in the construction of the maps.  The theoretical shear strength of the material is independent of temperature and located along the top of the map, with the regimes of plastic deformation mechanisms below it.  Constant strain rate contours can be constructed on the maps using the constitutive equations of the deformation mechanisms which makes the maps extremely useful.