压力对DNAN凝固过程的影响

为指导2,4-二硝基苯甲醚(DNAN)基熔铸炸药凝固工艺优化设计,采用自制的多点加压凝固测试装置测试DNAN在0.6、0.3 MPa和常压下凝固过程的温度变化和凝固速率,用工业CT和扫描电镜观测试样的缺陷分布情况,用密度仪测试试样的装药密度。试验结果显示:随着压力的升高,DNAN的过冷度和凝固速率均逐渐增大;在DNAN装药体中,凝固产生的体积收缩更多集中于装药体上部,而装药体下部中的弥散性缺陷得到显著降低;DNAN晶粒生长的有序度得到提高,晶粒间空隙逐渐减少,装药相对密度由95.1%提高到了96.7%。上述研究表明,压力作用对DNAN的凝固过程影响较为明显,施加较低的压力即可有效提升装药质量。

Effect of Pressure on DNAN Solidification Process

In order to optimize the solidification process of DNAN-based melt-casting explosives, the temperature-time curves and solidification rate of DNAN solidification process under 0.6MPa, 0.3MPa and atmospheric pressure respectively were measured by a home-made pressured solidification multi-point type measuring device. The distribution of solidification defect of these solidification samples was observed by industrial CT and SEM, respectively. The charge density of these solidification samples was measured by density instrument. Results show that the undercooling and solidification rate increase gradually with increasing pressure. In DNAN charge, the volume shrinkage caused by solidification is more aggregated in the upper part of charge, while the diffuse solidification defect in the lower part of charge decrease significantly with increasing pressure. The orderliness of DNAN grain growth is improved, the space between grains is gradually reduced, and the relative density of charge increase from 95.1% to 96.7%. These results indicate that DNAN solidification process is significantly affected by pressure. The high quality DNAN charge can be achieved by applying a lower pressure on solidification process.