A-Ⅸ-Ⅱ炸药柱的湿热老化行为

Hygrothermal Aging Behaviors of A-Ⅸ-Ⅱ Explosive Grain

为了研究含Al和RDX压装混合炸药装药对湿热环境的适应性,将Ф20mm、Ф40mm、Ф60mm、Ф84mm的A-Ⅸ-Ⅱ压装炸药柱在71℃、相对湿度65%的环境条件下老化52d,跟踪记录了药柱的体积、抗压强度、质量、Al粉活性、分解热、真空安定性(VST)、爆发点随老化时间的变化,并用X线断层摄影仪、扫描电镜观察其微观结构。结果表明,湿热老化使药柱体积发生不可逆膨胀、抗压强度变小、部分Al粉被氧化、分解热降低,老化初始阶段变化较快,老化7d后变化趋缓;老化52d后爆发点温度没有明显降低,VST放气量没有增加,表明炸药的热安定性没有退化;药柱的结构完整性存在尺寸效应,直径在60~84mm存在临界值,大于临界值的药柱老化后内部容易产生裂纹;老化后钝感黏结剂破碎、脱粘,导致药柱的抗压强度变小;老化后部分Al粉失活,使得炸药的分解热减少。

To study the hygrothermal environment adaptation of pressed mixed explosive charge with A1 and RDX, pressed A-IX-Ⅱ explosive grains with Ф20mm ,Ф40mm ,Ф6 0 m m and Ф 8 4 mm were aged 52 days under the environ-mental conditions of 71℃ and relative humidity of 65% , the changes in volumes, compressive strength, mass,alu-minum powder activity, decomposition heat, vacuum stability test （VST） and explosion temperature of the grains with time were tracked and recorded. Their microstructures were observed by X-ray computed tomography and scanning electron microscope. The results show that hygrothermal aging makes the volumes of grains occur irreversi-ble expansion, compressive strength decrease, part of A1 powder be oxidized, and decomposition heat decrease, which change rapidly in the initial stage of aging and slowly after aging 7 days, explosion temperature does not re-duce significantly and the amount of gas of VST does not increase after aging 52 days indicating that the thermal stability of the grain is not degraded. The structure integrality of grain has size effect, there exists a critical value of 60-84 mm in diameter,grains are easy to generate internal crack when their diameters are greater than the critical value of aging. The insensitive binder breakage and debonding after aging cause the decrease of compressive strength of grain and inactivation of part of A1 powder, making the decomposition heat of explosive reduce.