Characterization of near-surface conditions of machined ceramics by use of x-ray residual stress measurements

In order to optimize efficiency of machining, surface properties and strength of machined ceramics, the complex relationships between machining parameters and strengthcontrolling surface effects have been studied using a newly developed method for the determination of microstrain and residual stress depth profiles by X-ray diffraction techniques, bending tests and fracture mechanical calculations. The results allow to quantify the effects of damage processes and residual stresses on the strength of ceramics. Cases of lapping and grinding are shown, where on one hand surface damage (lapping of Alsub2Osub3, grinding of Alsub2Osub3 and Sisub3Nsub4), and on the other hand macroscopic residual stresses (lapping of Sisub3Nsub4) are the dominating effects on the bending strength.