摘要
为探究铝/聚四氟乙烯(Al/PTFE)活性材料在动态载荷下的力学行为及其点火机理,采用分离式霍普金森压杆对不同成型压力下所制备的Al/PTFE试件进行动态压缩试验。试验结果显示,当应变率为2960~5150 s-1时,Al/PTFE试件在动态加载下呈现出典型的弹塑性力学行为,成型压力为50~150 MPa时,Al/PTFE试件的屈服强度和硬化模量并未表现出应变率效应。成型压力30~80 MPa时,Al/PTFE试件的速度点火阈值随成型压力的增加从28.77 m·s-1缓慢升高到29.22 m·s-1,材料的点火延迟时间始终保持在600~700μs。当成型压力达100 MPa时,Al/PTFE试件的速度点火阈值大幅下降至26.60 m·s-1,且随着撞击速度的提高,活性材料的点火延迟时间由1000~1100μs降到600~700μs。结合扫描电镜结果可知,成型压力为100~150 MPa时,活性材料内部的局部大尺寸孔洞是材料速度点火阈值下降的重要因素。Al/PTFE活性材料的撞击引发点火特性主要与外部载荷和内部微观形貌有关。
In order to investigate the dynamic behavior and ignition mechanism of Al/polytetrafluoroethylene(PTFE)reactive material under dynamic loading,a Split Hopkinson Pressure Bar(SHPB)was used to conduct the dynamic compression experiment on reactive materials with different molding pressure. Experimental results show that the Al/PTFE reactive material exhibits typical elastic-plastic mechanical behavior under dynamic loading at strain rate ranging from 2960 s-1 to 5150 s-1. The yield strength and hardening modulus of Al/PTFE reactive materials do not show strain rate effect when the molding pressure is 50-150 MPa. The velocity ignition threshold increases slowly from 28.77 m·s-1 to 29.22 m·s-1 with the molding pressure. When the molding pressure increases to 100 MPa,the velocity ignition threshold drops significantly to 26.60 m·s-1. With the increase of the impact velocity,the ignition delay time for reactive materials with the molding pressure of 100-150 MPa decreases from 1000-1100 μs to 600-700 μs,while that of reactive materials with the molding pressure of 30-80 MPa maintains at 600-700 μs. Combining with results of Scanning Electron Microscopy,it is found that the local larger pores inside the reactive materials with higher molding pressure is the main factor for the sudden drop of the velocity ignition threshold. Therefore,the impact ignition characteristics of Al/PTFE reactive materials are mainly related to the external loading form and the internal micro-morphology.
作者
李尉
任会兰
宁建国
刘元斌
LI Wei;REN Hui⁃lan;NING Jian⁃guo;LIU Yuan⁃bin(State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China)
出处
《含能材料》
EI
CAS
CSCD
北大核心
2020年第1期38-45,共8页
Chinese Journal of Energetic Materials
基金
国家自然科学基金(11872124)
爆炸科学与技术国家重点实验室课题(YBKT19-11)
