Atomistic mechanisms in the plasticity of energetic crystal HMX*

The energetic molecular crystal cyclotetramethylene tetranitramine (HMX) is a key constituent in common plastic bonded explosives. Its plastic deformation under shock conditions is important in reaction initiation and detonation. In this work we identify, using atomistic simulations, the slip systems in b-HMX and compute the critical resolved shear stresses for dislocation motion. We also evaluate the mobility of dislocations in various slip systems and the likelihood of cross-slip. The implications of these results for the overall physical picture of plasticity in HMX are discussed.

A. Pal, R.C. Picu, Modelling Simul. Mater. Sci. Eng. 26 (2018) 045005
M. Khan, A. Pal, R.C. Picu, Modelling Simul. Mater. Sci. Eng. 26 (2018) 085009
M. Khan, R.C. Picu, J. Appl. Phys. 126 (2019) 155105