Toward the defect engineering of energetic materials: A review of the effect of crystal defects on the sensitivity

Defects always exist in the applied energetic materials (EMs) and have a vital influence on ignition mechanism and further sensitivity. The defect engineering of EMs aims to obtain the understandings of defect effects on properties and performances and use these understandings to create new EMs to satisfy the specified requirements. This article reviews the effect of crystal defects on the sensitivity with a wide range, i.e., the defects include various types, such as point defect (vacancy, orientational defect and element doping), line defect (dislocation), planar defect (twin, shear band, crack and surface defect) and volume defect (void); and four types of sensitivities are covered, including shock sensitivity, impact sensitivity, thermal stability and laser sensitivity. In addition, we summarize the origin of the defect-induced enhancement of sensitivity, as that the molecules of defects possess thermodynamic and kinetic advantages in the external stimuli induced decomposition over those in the perfect bulk. Besides, we present a perspective of the defect engineering of EMs, in which the structure–activity relationship and the efficient creation and use of defects are put forward.