The mechanical properties of a polymer bonded explosive based on HMX thermally aged under 75 ℃ were investigated. The variation of the density of the samples is less than 0.003 g · Cm -3 before and after thermal aging. The results of the mechanical testing show that the compressive and tensile properties changed reversely after thermally treatment, that is, the compressive properties were decreased while the tensile properties were increased. Combined using the computer tomography ( piCT), X-ray photoelectron spectrometer (XPS) and ultrasonic microscope, it shows that the density decrease of the PBX maybe resulted from the volatilization of the lower-melting-point indigent of the formulation, that is the reason for the decrease of the compressive strength. Contrarily ,the interface bonding between the HMX crystals and the binder has been improved through the thermally aging such that the tensile mechanical properties as well as the tensile creep performance have been improved.%针对HMX基高聚物粘结炸药(HMX基PBX)经高温老化后虽然密度降低但是力学性能变化规律性不强的问题,将试样之间密度差控制在0.00 3g· cm-3范围内,经过不同时间75C高温老化后测试其力学性能变化.结果表明,HMX基PBX经过高温老化后,呈现出压缩性能降低而拉伸性能增强的反向变化现象.结合高精度X射线断层扫描(μCT)、超声显微、X光电子能谱(XPS)等检测结果对这一反向变化现象进一步分析,认为经过75℃高温老化后,由于HMX基PBX中低熔点组分挥发,密度降低,导致压缩性能降低,但在高温老化中,晶体损伤未明显增加,晶体与粘结剂界面作用增强,因此,受其影响较大的拉伸性能不但未降低,反而存在改善的趋势.
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