AbstractIn the present work a parametric investigation on hydrogen evolution by hydrolysis of ball‐milled Al/graphite composite materials with water is reported. The results showed that the addition of NaCl produced some favorable effects on the completeness of the Al hydrolysis reaction with water, particularly at low NaCl weight percentage levels, but deteriorated the Al reactivity due to large size agglomerates formed during milling process. Using a fine aluminum powder could improve the aluminum hydrolysis reactivity and increase hydrogen generation rate. The hydrogen evolution measurements showed that Al in pellet form exhibited poor hydrolysis reactivity, and increasing the aging time significantly degraded the Al reactivity. The hydrogen evolution rate of the Al/graphite composite materials is also dependent on reaction temperature, and the maximum hydrogen generation rate of 52.4 cm³ min⁻¹ g⁻¹ Al was obtained if the reaction temperature was increased to 75 °C.