In this research a composite structure containing of a TiB2 matrix with dispersed Al2O3 particles was obtained via mechanical alloying of Al, TiO2 and B2O3 powder mixture. The mixture was milled for different lengths of time. Phase evolutions of the milled powder mixture were investigated. Powder particle characteristics were evaluated by XRD, SEM and TEM techniques. The XRD results reveal that the reaction begins during first 10 h milling by formation of TiB2 and Al2O3¬ phases and further milling causes partial amorphization of powder mixture. SEM micrograph of the sample milled for 30 h exhibited ultrafine particles of Al2O3-TiB2, but TEM images show that particles consist of some grains in the range of nano-size. The mean crystallite size of final product is about 25 nm.
