The production of multi-layers multi-materials coatings requires the knowledge of their mechanical behaviour, and specially of the internal residual stresses fields. The method based on layers removal has been previously explained: for metallic pieces, the more usual removing mode is E.C.M. We have extended this model to the case of multi-materials coatings. Nevertheless, for ceramics materials (not electrical conductors), we had to use special cutting tools, after having verified that this process did not disturb significantly the considered stress field. We have thus analyzed various industriel samples, and explained the results with the blocks method.

Plastic deformation treatments of hardened metallurgical products are becoming an usual technique of industries which transform semi-finisched products. They are now used systematically in residual stresses relaxation.