Molecular Dynamics Simulation of Temperature Effect on the Morphology of ε-CL-20

In order to study the effect of temperature on the crystal morphology of hexanitrohexazazisovudane (CL-20) in ethyl acetate/trichloromethane solvent system, the molecular dynamics simulation method was used to calculate the CL-20 crystal energy and crystal habit by using the corrected attachment energy model. The simulated and experimental crystal morphology of CL-20 at different temperatures(293, 303, 313, 323, 333K) were also compared. The results show that the crystal morphology of CL-20 can be affected significantly by temperature. As the temperature increases, the crystal morphology of CL-20 tends to become an aspherical shape. The CL-20 crystals with a higher spheroidization degree can be obtained at the crystallization temperature of 293K. The temperature has distinct influences on different crystal planes, and crystal planes including (2 0 0), (0 1 1), and (2 0 -1) are easily affected by temperature. The absolute values of the adhesion energy for the above three crystal planes are larger compared to that of other planes, so the growth rates of the crystal plane are faster. The surface area ratio of these CL-20 crystal planes decrease, and these planes cannot be retained in the final CL-20 crystals. When the temperature is 333K, the adhesion energy of (2 0 -1) crystal plane is greatly affected, and finally, the crystal plane is exposed in the morphology of CL-20 crystals. © 2021, Editorial Board of Journal of Explosives & Propellants. All right reserved.