AP-CMDB推进剂微观结构及药形尺寸对低温力学性能的影响

Effects of Microstructure and the Form and Size on Mechanical Properties of AP-CMDB Propellant at Low Temperature

为研究溶剂压伸法制备的AP-CMDB推进剂低温发动机试验易产生碎药的原因,采用扫描电子显微镜(SEM)和能谱仪(EDS)观察了AP-CMDB推进剂样品的微观结构;通过测试样品的线膨胀系数,研究了AP颗粒与黏合剂体系的线膨胀匹配性;讨论了药形尺寸对推进剂低温抗冲强度的影响。结果表明,溶剂压伸法制备的APCMDB推进剂药柱中存在大量微孔和少量微裂纹,AP颗粒团聚明显,Al颗粒与黏合剂体系间出现严重的界面脱粘;AP颗粒与黏合剂体系间的线膨胀匹配性较差;壁厚1.5mm的单孔管状药柱的低温(-40℃)抗冲强度低于壁厚4.5mm的,套管结构药柱的低温(-40℃)抗冲强度低于单孔管状药柱的。AP-CMDB推进剂低温碎药的形成与其微观结构、力学性能及药形尺寸有关。

To study the cause of producing cracking propellant in engine test at low temperature for AP-CMDB propellant prepared by solvent-extrusion method,the microstructure of the sample was observed by scanning electron microscopy and energy spectrometer.The linear expansion matching of AP particles and binder system was studied via measuring the linear expansion coefficient of AP-CMDB propellant.The effects of the form and size on the impact resistance of the propellant were studied.The results show that there are lots of micro-holes and a few micro-cracks in the propellant grain prepared by solvent-extrusion method,the agglomeration of AP particles is obvious,and the Al particles and binder system appear serious interface debonding.The linear expansion matching between AP particles and binder system is poor.The impact resistance of single-tube propellant grain with wall thinckness of 1.5mm is lower than that of propellant with wall thickness of 4.5mm at-40℃.The impact resistance of propellant grain with casing structure is lower than that of propellant with single-tube structure.The formation of cracking propellant at low temperature for AP-CMDB propellant correlates with the microstructure,mechanical property,form and size of the propellant.