Coherency strain energy

The coherency strain energy introduces an additional barrier to spinodal decomposition, which causes a shift on the temperature-composition phase diagram of the chemical spinodal, defined by d2filom/dc% = 0, to the coherent spinodal, defined by... 

Martensitic transformations involve a shape deformation that is an invariant-plane strain (simple shear plus a strain normal to the plane of shear). The elastic coherency-strain energy associated with the shape change is often minimized if the martensite forms as thin plates lying in the plane of shear. Such a morphology can be approximated by an oblate spheroid with semiaxes (r, r, c), with r c. The volume V and surface area S for an oblate spheroid are given by the relations... 

The coherency strain energy per unit volume transformed is... 

In the case of DIIM the coherency strain energy stored in a thin diffusional coherent layer is expressed as ... 

Figure 8.6 shows the calculated coherency strain energy map (CSEM) of rhombohedral AI2O3 with Fe203 as a solute from Eq. (8.2). In this figure the maximum coherency strain energy appears on the (0001)C plane in terms of the... 

Figure 8.6. Coherent strain energy map (in MJ/m ) of Al203/Al203(Fe203) for an Fe203 concentration of 5 mol% (with Sc/So 0-94) in a coherent diffusion zone. The axes represent the interplanar angles between the surface normal of the considered plane and those of an a(2IIO) plane (a) and an m(0l 10) plane (jS).

Figure 8.9. Comparison between capillary energy lyt/r, r the average radius of grain boundary curvature) and calculated coherency strain energies stored in a (Bao.8Pho,2)Ti03 layer on BaTiOs. Specific grain boundary energy is assumed to be 0.5...

Hay, R. S., Coherency strain energy and thermal strain energy of thin films in any crystal system, Scripta MetalL, 26, 535-40, 1992. 

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