Recent studies have shown that Y3Al5O12 (YAG - yttrium aluminum garnet) and Al2O3 composites are chemically stable at high temperatures when produced by unidirectional solidification. In this method, the material is slowly solidified immediately after passing through a melting zone. However, this complexity procession has encouraged other routes. Among them, the usual sintering of Al2O3 and Y2O3 (or YAG) powders. In this present work, Al2O3 and YAG powders were produced using a high-energy milling of Al2O3 and Y2O3 precursor powders followed by a thermal treatment step. These powders were characterized using quantitative XRD techniques, BET, SEM and TEM. The complete YAG formation was obtained at 1,400°C.