FGM composites have been prepared using Al2O3 and NiAl powders. Pure Al2O3 and NiAl layers have been joined trough a mixed layer (70% vol Al2O3 and 30% vol NiAl). The residual stress in Al2O3 has been experimentally determined by monitoring the stress-induced frequency shift of a fluorescence band due to chromium impurities naturally present in the Al2O3 powder. The stress in Al2O3 is compressive increasing in absolute value when moving from pure alumina to pure NiAl. In the mixed Al2O3/NiAl the stress present large fluctuations from site to site due to local microstructural inhomogeneities.
