The individual and combined effects of Bi and In on the morphology change and reactivity towards hydrogen release of Al during mechanochemical preparation of binary and ternary Al composites were determined. Subsequently, successfully prepared reactive composites were hydrolyzed with neutral pH waters under ambient conditions with the purpose of hydrogen generation. Reactive ternary composites were analyzed by scanning electron microscopy and X-ray diffraction. Results showed that phases found in the Al-Bi-In composites were Al, Biln, BiIn3, and Bi3In5. In some cases Bi and In that did not partake in intermetallic Bi-In phase formation were also found. The intermetallic phases between Bi and In were identified and characterized. It was concluded that the reactivity of ternary composites towards hydrogen yield were governed by the in situ formed intermetallic phases, and the remaining Bi and In that did not undergo intermetallic phase formation. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.