微纳米HMX基PBX力学、导热性能及药片撞击感度

Mechanical,Thermal Conductive Properties and Tablet Impact Sensitivity of Micro-nano-HMX Based PBX

为了研究微纳米尺度下颗粒尺寸对于炸药撞击感度的影响规律及作用机制,将三种奥克托今(HMX,粒径为100~300 nm,1~2μm,10~20μm)基高聚物粘接炸药(PBX)造型粉压制成表观密度分别为1.74 g·cm^(-3)与1.50 g·cm^(-3)的PBX样品,研究了HMX粒径与表观密度对PBX样品压缩力学性能、导热性能以及药片撞击感度的影响。使用扫描电镜观察了样品受落锤撞击前后的微观形貌,并通过自行设计的试验装置测试了落锤撞击加载过程中样品的受力情况。结果表明,PBX样品的压缩强度、压缩模量、导热系数及热扩散系数均随HMX粒径的减小而显著增大。在相同表观密度下,PBX样品的撞击感度随HMX粒径减小而明显降低;对于含同种粒径HMX的PBX样品,撞击感度随表观密度的增加而略微升高。撞击作用下HMX粒径较大的样品主要发生孔穴压缩与颗粒破碎,HMX粒径较小的样品主要发生颗粒层的剪切滑移。在相同撞击条件下,作用于试样力的峰值随表观密度的增大或粒径的减小而增大。认为炸药颗粒细化所带来的撞击感度降低是细化后炸药内部孔隙尺寸减小、孔隙结构均匀化程度提高以及导热性能提升等因素共同作用的结果。

To investigate the influence law of particle size on the impact sensitivity of explosives in micro-and nano-scale and mechanism of action,the polymer-bonded explosives(PBXs)samples with apparent density as 1.74 g·cm-3 and 1.50 g·cm-3 were pressed from octogen(HMX,100-300 nm,1-2μm and 10-20μm)based PBX molding powder.The effect of HMX particle size and apparent density on the compression mechanical properties,thermal conductive properties and tablet impact sensitivity of PBX samples were studied.The micromorphology of samples before and after impact with drop hammer was observed by SEM,and the histories of force acting on samples during drop hammer impact loading were measured by a self-designed test device.Results show that the compressive strength,compressive modulus,thermal conductivity and thermal diffusivity of PBX increase dramatically with decreasing particle size of HMX.In same apparent density,the impact sensitivity of PBX decreases significantly with decrease of HMX particle size;for PBX samples with HMX of same particle size,the impact sensitivity increases slightly with the increase of apparent density.Under impact action,HMX samples with larger particle size mainly happen the pore compression and particle crack and HMX samples with smaller particle size mainly happen the shearing slip of particle layer.Under same impact condition,the peak of force acting on sample increases with increasing apparent density or decreasing particle size.Considering that the decrease of impact sensitivity caused by explosive particle refinement is the result of the combined effect of the edecrease of pore size,uniformity of pore structure,and enhancement of thermal conductivity etc.factors.