a) b)  

 

Fig. 64: a) The SEM observation of this sample shows the rafted ' precipitates microstructure which developed after the thermo-mechanical heat treatment described above. b) With a rafted microstructure, the lattice mismatch depends on the considered direction. The temperature dependence of the lattice mismatch was measured in parallel <200> and perpendicularly <002> to the rafts in order to determine the straining state of the material.