热刺激作用下FOX-7颗粒形貌演化对其力学特性及感度的影响

Effect of Morphology Evolution on Mechanical Properties and Sensitivities for FOX-7 Particles Under Thermal Stimulus

为研究1,1-二氨基-2,2-二硝基乙烯(FOX-7)颗粒在热刺激作用下的形貌演化过程及其对力学特性及机械感度的影响规律,选取4种具有典型粒径及形貌差异的FOX-7颗粒,通过控制加热时间及温度,并采用扫描电子显微镜、压缩刚度实验、机械感度测试等手段研究了FOX-7颗粒在受热后的形貌、力学特性及机械感度演化历程。结果表明,受热并恢复室温后,FOX-7颗粒表面会出现裂纹,随着加热温度升高或加热时间延长,大粒径颗粒(>100μm)的表面裂纹进一步扩展生长并形成贯穿,颗粒层状开裂、发生片状剥离;小粒径颗粒(<100μm)的表面裂纹不会随着加热温度升高或加热时间延长而进一步扩展生长。采用Kawakita方程对加热前后的FOX-7颗粒压制曲线进行拟合,发现受热后颗粒模量均增大,而小粒径颗粒的增幅更大。在颗粒粒径较大的情况下,FOX-7机械感度相对较低,在受热并恢复室温后仍可维持较低的机械感度;当颗粒粒径较小,FOX-7机械感度相对较高,在受热并恢复室温后,机械感度显著上升,可能与其模量增幅更大有关。

In order to study the morphology evolution of 1,1-diamino-2,2-dinitroethylene(FOX-7)particles under thermal stimulus and its influence on mechanical properties and mechanical sensitivities,four kinds of FOX-7 particles with typical size and morphology differences were selected.By controlling heating time and temperature,the morphology,mechanical properties and mechanical sensitivities evolutions of FOX-7 particles after heating were studied by scanning electron microscope,compressive stiffness experiment and mechanical sensitivities tests.The results show that the surface cracks of FOX-7 particles appear after heating and returning to room temperature.With the increase of heating temperature or heating time,the surface cracks of large-size particles(>100μm)grow and break through,thus the particles crack in layers and exfoliate.While,the surface cracks of small-sized particles(<100μm)do not grow with the increase of heating temperature or heating time.Kawakita equation was used to fit the compaction curves of FOX-7 particles before and after heating.It is found that the modulus of FOX-7 particles increase after heating,and the increase is even greater for small particle size.Under the condition of larger particle size,FOX-7 has relatively low mechanical sensitivities,and still maintains low mechanical sensitivities after being heated and returning to room temperature.When the particle size is small,the mechanical sensitivities of FOX-7 are relatively high,and after heating and returning to room temperature,the mechanical sensitivities increase significantly,which may be related to the greater increase of modulus.