Deformation mechanism maps for applications at high temperatures

Deformation mechanism maps provide a very simple and convenient method of displaying mechanical properties data at high temperatures. Several different types of maps are available, and these are discussed with reference to polycrystalline Al₂O₃ and MgO. Ambipolar diffusion is important in ceramic materials, and this leads to four different types of diffusion creep which may be illustrated directly on the deformation mechanism maps. In practice, the accuracy of the maps depends on the purity level, and this is demonstrated by comparing maps for nominally pure Al₂O₃ and Al₂O₃ doped with MgO above the solubility limit.