热损伤奥克托金(HMX)缺陷的X射线小角散射研究

A small-angle X-ray scattering study of micro-defects in thermally treated HMX

奥克托金(HMX)在温度作用下,会发生热膨胀、相转变、热分解等物理、化学变化,导致在材料内部产生大量缺陷,进而会对其宏观性能造成明显影响.为了深入了解热损伤HMX内部的缺陷演化,本文采用X射线小角散射和原子力显微技术研究了热损伤HMX的内部缺陷.结果发现HMX在180℃相变过程中散射曲线有明显的变化,颗粒内部生成了大量10nm左右的孔洞,随着加载时间延长,其尺寸增大到25nm,数量明显降低.当HMX在190℃、200℃保温5h时,由于HMX热分解内部有新缺陷生成,小角散射发现其尺寸约为5至8nm,随着加载温度升高,其数量增加.

The defects in HMX, induced by thermal expansion, phase transition and chemical decomposition, have large effects on the performance of HMX. In this work, the defects of HMX samples under heat treatment are characterized by small angle X-ray scattering （SAXS） and atomic force microscopy. A large number of pores with an average size of 10 nm are found during theβ-δ phase transition of HMX （180 °C）, and the pores increase in size and decrease in number with time increasing. A new population of small pores with sizes of 5-8 nm are produced in HMX during the thermal decompositions （190 °C and 200 °C）. The size and the number of the small pores increase with temperature increasing.