高温作用后HMX基PBX热损伤表征试验研究

To study the thermal damage behavior of cyclotetramethylenete-tranitramine (HMX) based polymer bonded explosive (PBX) undergoing high-intensity thermal insult (room temperature to 200℃, 10h), micron-scale computed tomography (micro-CT) was used to quantitatively characterize the changes of the micron-scale porosity of HMX based PBX before and after heating. Combined with the changes of sample size, mass, true density and micro-morphology, the thermal damage of HMX based PBX was analyzed.The results show that the sample volume, mass and true density do not change obviously at 160℃. The volume expansion of the sample is observed to be irreversible after treatment at 180℃, and the true density decreases by 8.75%. However, the mass does not change. After treatment at 200℃, the true density reduces up to 9.92% due to the decrease of mass, volume expansion, thermo-induced porosity and cracks on the surface of samples. According to the microscopic observation and statistical calculation, the porosity of the sample increases first and then decreases with the increase of the test temperature. The maximum porosity is 7.81% at 180℃ and then decreases at 200℃. Herein, it is considered that a large number of cracks and debonding between HMX grains caused by phase transformation at 180℃, which makes the porosity of PBX increase. Then the refinement of the grains fills a part of the voids resulting in a recovery of porosity at 200℃. However, the change of porosity is not affected by binder since no melting occured.