Study on the self sustained reactions in an Al-TiO2 composite powder produced by high-energy mechanical milling

A mixture of Al and TiO2 powders after high-energy mechanical milling was submitted to self sustained reactions to understand the influence of mechanical activation on the kinetics and products of the reactions. It has been found that mechanical milling the powders significantly lowered the ignition temperature of the reactions by refining the Al/TiO2 composite structure. Shorter milling time leads to the formation of more amounts of metastable phases and coarse microstructure, which is in the similar scale in the mechanical milled samples. In contrast, equilibrium phases and a fine microstructure were found in the samples having a fine Al/TiO2 composite structure produced with a longer milling time. Mechanical milling has greatly improved the kinetics of the reactions between the two components. (c) 2006 Elsevier B.V. All rights reserved.