Authors: Yong He | Yansong Yang | Yuan He | Lei Guo | Zhichao Sun | Chuan Ting Wang
Source: Chinese Science Bulletin (Chinese Version) (article, 2023-09-01)
Field: Materials Science — Materials Chemistry

Recent progress in impact-induced reaction mechanisms of reactive alloys <p indent="0mm">Destruction by munitions mainly relies on their warheads, and research on improving the destructive effectiveness of warheads has focused on new explosives, improving the warhead structures, and adopting new types of destructive elements. The limitations of the single kinetic damage mechanism and damage mode of the inert damage element largely restrict the enhancement of destructive effectiveness of conventional warheads. Therefore, a new type of reactive material has been developed, namely, reactive alloys, which include metal composite materials, amorphous alloys, and high-entropy alloys. The common characteristic of these alloys is that they contain reactive metal elements (Al, Mg, Ti, Zr, etc.), which easily undergo oxidation under high-temperature conditions. Compared with the traditional metal-polymer and other reactive composites, these alloys have higher density and strength, excellent mechanical properties, and broader application prospects. The exothermic reaction properties of reactive alloys under high-velocity impact conditions facilitate strong ignition and detonation effects and considerably improve their destructive effectiveness. Current researchers have mainly investigated the impact-induced reaction mechanisms of reactive alloys by conducting various impact tests. They found that the mechanism involves several stages: From material crushing to materials undergoing reaction, i.e., the material is first crushed by the impact compression and dispersed into many fine particles, and the temperature of the material increases rapidly in the meantime, and finally, an intense oxidation reaction occurs in the material after being heated. This paper focuses on three aspects that need to be addressed during the impact-induced reaction mechanisms of reactive alloys: (1) The fragmentation mechanism and size distribution trend of the generated fragments after a material impacts the target, (2) the relation between the transient temperature and fragment size due to the impact and adiabatic shear, and (3) reaction temperatures and size thresholds for the fragments to undergo the chemical reactions. Recent research progress on these three problems was summarized to reveal the reaction mechanism of reactive alloys. Because reactive alloys have excellent mechanical properties, they can be used in various future armor-piercing munitions, shaped charges, and fragmentation materials. They can also be directly made into reactive material shells. Conducting subsequent work will be conducive to promoting the application of reactive alloys. In the future, reactive alloys can be applied to fabricate more destructive elements to realize the integration of structure and function, which will substantially improve the reliability of the warheads, simplify the design space, realize high efficiency of the munition’s destructive effectiveness, and remarkably improve the integration of structure and function of warheads. Materials science ; Chemistry High-Velocity Impact and Material Behavior ; Energetic Materials and Combustion ; Ion-surface interactions and analysis