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Mechanochemical Mechanism For Fast Reaction Of Metastable Intermolecular Composites Based On Dispersion Of Liquid Metal, Valery I. Levitas, Blaine W. Asay, Steven F. Son, Michelle Pantoya
Mechanochemical Mechanism For Fast Reaction Of Metastable Intermolecular Composites Based On Dispersion Of Liquid Metal, Valery I. Levitas, Blaine W. Asay, Steven F. Son, Michelle Pantoya
Valery I. Levitas
An unexpected mechanism for fast reaction of Alnanoparticles covered by a thin oxide shell during fast heating is proposed and justified theoretically and experimentally. For nanoparticles, the melting of Al occurs before the oxide fracture. The volume change due to melting induces pressures of 1–2 GPa and causes dynamic spallation of the shell. The unbalanced pressure between the Al core and the exposed surface creates an unloading wave with high tensile pressures resulting in dispersion of atomic scale liquid Al clusters. These clusters fly at high velocity and their reaction is not limited by diffusion (this is the opposite of …
Coupled Phase Transformation, Chemical Decomposition, And Deformation In Plastic-Bonded Explosive: Models, Valery I. Levitas, Bryan F. Henson, Laura B. Smilowitz, David K. Zerkle, Blaine W. Asay
Coupled Phase Transformation, Chemical Decomposition, And Deformation In Plastic-Bonded Explosive: Models, Valery I. Levitas, Bryan F. Henson, Laura B. Smilowitz, David K. Zerkle, Blaine W. Asay
Valery I. Levitas
A continuum thermomechanochemical model of the behavior of a plastic-bonded explosive (PBX) 9501 formulation consisting of the energetic crystal octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) embedded in a polymeric binder is developed. Our main focus is on the study of the β↔δphase transformations (PTs) in crystalline HMX under a complex pressure-temperature path. To reproduce the pressure-temperature path, in particular during heating of PBX inside of a rigid cylinder, the β↔δ PTs in HMX are coupled to chemical decomposition of the HMX and binder leading to gas formation, gas leaking from the cylinder, elastic, thermal, and transformational straining as well as straining due to mass …
Coupled Phase Transformation, Chemical Decomposition, And Deformation In Plastic-Bonded Explosive: Simulations, Valery I. Levitas, Bryan F. Henson, Laura B. Smilowitz, David K. Zerkle, Blaine W. Asay
Coupled Phase Transformation, Chemical Decomposition, And Deformation In Plastic-Bonded Explosive: Simulations, Valery I. Levitas, Bryan F. Henson, Laura B. Smilowitz, David K. Zerkle, Blaine W. Asay
Valery I. Levitas
Numerical simulations of the heating with constant rate of a PBX (plastic-bonded explosive) 9501 formulation consisting of the energetic crystal HMX embedded in a polymeric binder inside of a rigid cylinder is performed. The continuum thermo-mechanochemical model of the behavior of a PBX 9501 developed in the preceding paper [V. I. Levitas, B. F. Henson, L. B. Smilowitz, D. K. Zerkle, and B. W. Asay, J. Appl. Phys.102, 113502 (2007)] is applied. The model describes the β↔δphase transformations in crystalline HMX, chemical decomposition of the HMX and binder leading to gas formation, gas leaking from the cylinder, elastic, thermal, and …