SIMPLE TECHNIQUE FOR OBSERVING SUBSURFACE DAMAGE IN MACHINING OF CERAMICS

A simple technique is proposed for directly observing subsurface damag e in the machining of ceramics. The technique requires two polished sp ecimens and an optical microscope with Nomarski illumination for exami nation. The subsurface damage created by the grinding of an alumina ce ramic is investigated using this technique. The mode of damage is iden tified as intragrain twinning/slip, and intergranular and transgranula r cracking. Chipping along the twinned planes and along the transgranu lar crack planes, and dislodgement of the intergranularly debonded gra ins are suggested to be the mechanisms of material removal in the mach ining of this alumina ceramic.