Characterization of MCX-6002 and MCX-8001

Knowledge about properties of explosive composition is important regardless of the applications. The performance of explosive compositions depends on detonation velocity and detonation pressure. The munition sensitivity depends on the critical diameter of the explosive filling in order to fulfill the IM requirements. The MCX-6002 and MCX-8001 studied in this report are new compositions developed with increased critical diameter to withstand shock threats from bullet attack, fragment impact, sympathetic detonation or shaped charge jet attack. The explosive compositions MCX-6002 and MCX-8001 are developed and produced by Chemring Nobel. They are melt-cast compositions for application as filling in large caliber munitions like 120 mm and 155 mm shells. We have characterized MCX-6002 and MCX-8001 due to the potential for utilisation in these ammunition types. Both compositions have TNT as binder. The solid filler is a mix of NTO and RDX/HMX. Nominal content for MCX-6002 is NTO/TNT/RDX (51/34/15) and for MCX-8001 NTO/TNT/HMX (52/36/12). MCX-6002 and MCX-8001 have been characterized with regards to critical diameter, detonation velocity and detonation pressure. Cylindrical charges with diameter from 11 mm to 37 mm were casted as test items for the tests. The quality of the charges was examined by X-ray, showing inclusion of air in all charges. This is porosity and pores/bubbles in the structure. Empty space was also observed in charges with a large diameter. However, the charges casted for detonation velocity and detonation pressure determinations had in the bottom a quality that could justify testing. To test the critical diameter of MCX-6002, cylindrical charges of five different diameters were glued together to three test items with diameter from 11 mm to 26 mm. The test results showed a critical diameter smaller than 11 mm. Three conical charges with diameter from 30 mm to 3-4 mm were casted and tested. These gave an average critical diameter of 10 mm. To test the critical diameter of MCX-8001, three test items with diameter from 11 mm to 26 mm glued together from five cylindrical charges of different diameters were used. All test items had a critical diameter smaller than 11 mm. Detonation velocity and pressure were tested with charges having diameter of 36+ 2 mm. For both MCX-6002 and MCX-8001, four charges were casted. Only the part of the charges having acceptable density was tested. Measured detonation velocities MCX-6002 were as follows: cast No. 1 7964 m/s (ρ =1.78 g/cm3 ), cast No. 2 7983 m/s (ρ =1.785 g/cm3 ), cast No. 3 7700 m/s (ρ =1.79 g/cm3 ) and for cast No. 4 7859 m/s (ρ=1.796 g/cm3 ). Average experimentally measured detonation velocity is not very different from what is theoretically calculated. Two tests of detonation pressure gave an average detonation pressure of 244.3 kbar, a result slightly lower than what is theoretically calculated. Measured detonation velocities for MCX-8001 were: cast No. 1 7836 m/s (ρ =1.768 g/cm3 ), cast No. 2 7700 m/s (ρ =1.781 g/cm3 ), cast No. 3 7426 m/s (ρ=1.758 g/cm3 ) and 7790 m/s (ρ =1.778 g/cm3 ) and cast No. 4 7842 m/s (ρ =1.786 g/cm3 ). The average detonation velocity obtained experimentally is slightly below what is theoretically calculated. Two tests gave average detonation pressure of 245.8 kbar, slightly below what is theoretically calculated.