Abstract
Inโdepth and inโplane response functions of photoโ and electroโstimulated probes have been modeled and quantitatively evaluated in order to assess their suitability to detect the highly graded residual stress fields generated at the surface of alumina hip joints. Optical calibrations revealed large differences in probe size, which strongly affected the detected magnitude of residual stress. A comparison between the responses of Raman and fluorescence probes in polycrystalline alumina showed that the depth of those probes spread to an extent in the order of the tens of microns even with using a confocal probe configuration. On the other hand, the electroโstimulated luminescence emitted by oxygen vacancy sites (F^+^ center) in the alumina lattice represented the most suitable choice for confining to a shallow volume the stress probe. This latter probe enabled us to reduce the measurement depth to the order of the tens of nanometers. We show maps of surface residual stress as collected on both mainโwear and nonwear zones of an alumina femoral head. A comparison among stress maps taken at exactly the same location, but employing different probes, revealed averaging effects on the stress magnitude detected with photoโstimulated probes, while proving the superior spatial resolution of the electron probe. ยฉ 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.