Abstract: The invention relates to a reversible hydrogen storage composition comprising lithium hydride which desorbs hydrogen when heated in a hydrogen environment to a temperature of 470° C. or more to form a hydrogenated state, and absorbs hydrogen when cooled to 420° C. or less, the temperatures of absorption and desorption being independent of the pressure of the hydrogen environment. A partially processed blend of powdered lithium hydride and catalytic amounts of other elements such as Fe, B, Ni, Co or C, added as micron or sub-micron sized powders and still present in the blend as a pure phase, can provide improved hydrogen storage.

Abstract: A treatment process for a composite comprising a matrix of a precipitation hardenable aluminum alloy and a particulate or short fiber ceramic reinforcement. The process includes hot and/or cold working the composite, subjecting the composite to a controlled heating step in which the composite is raised from ambient temperature to a temperature of from 250 to 450.degree. C. at a rate of temperature increase less than 1000.degree. C. per hour, and subjecting the resulting heat treated composite to a solution treating step.