Detonation heats of RDX-based non-ideal explosives containing 15, 30 and 45% of Al, (Al/ZrH2), TiH2 and ZrH2 were measured with a water calorimeter set. To get more information on the behaviour of the additives in the detonations performed in an argon atmosphere, the solid post-detonation products extracted from the calorimetric bomb were analysed to determine their elemental and phase compositions. The calorimetric heats were compared with the detonation energies obtained from thermochemical calculations. All the tested explosives produce more energy during detonation in the bomb than RDX itself, but only aluminium positively influences the total energy release. The results of thermal and XRD analyses indicate that post-detonation products contain mainly carbonaceous materials, metal oxides, unreacted hydrides and/or the metals. Unexpectedly TiH2 is the least reactive additive. At TiH2 content of 45%, the heat effect is close to that of calculated with an assumption of complete inertness of the additive. Moreover TiH2 and metallic titanium are present in the bomb residues in a significant amount.