Residual stresses due to machining of ceramic materials and their effect on strength.

The investigations deal with non-destructive X-ray analysis of residual surface stresses due to maching of ceramic materials like alumina, zirconia and silicon carbide. Systematic variations of the machining conditions lead to a close relationship between the elementary mechanisms of the machining procedures and the introduced residual stresses. From it can be concluded the correlation of the residual stresses with the bending strengths of the machined ceramic components that two overlapping effects are of importance: Up to a certain extent, residual stresses are able to improve or decrease strength. Severe machining conditions lead to a reduction of residual stresses and decreasing strength because of surface damages.