Thixotropic Reactive Munitions Material
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Solution Overview
Problem
Existing munitions technologies face challenges in achieving high enthalpic energy release and controlled fragmentation, with limitations in fragment velocity and structural integrity, particularly in incorporating reactive materials efficiently.
Innovation Solution
The use of thixotropic processing of energetic materials like aluminum with high-density materials such as tantalum or tungsten to create microstructures with bulk density equivalent to steel, combined with surface and near-surface processing methods to enhance fragmentation and reactivity, including patterned void arrays and texturing for controlled breakup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional munitions materials are used, then structural integrity is maintained, but fragment velocity and energy release are limited
Solution Approach 1:
The patent employs composite materials combining aluminum (energetic material) with tungsten or tantalum (high-density materials) to create a material that simultaneously achieves high fragment velocity through aluminum's energy release and maintains structural integrity through tungsten/tantalum's high strength and density. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The patent changes the physical and chemical parameters of the munitions material by using thixotropic processing to create a semi-solid composite material with controlled microstructure. This processing method enables the material to exhibit both the high energy release characteristics of aluminum and the structural properties of tungsten/tantalum, achieving enhanced fragment velocity while maintaining structural integrity during shock loading and gas-dynamic expansion.
2Use of energy by moving object
If reactive materials are incorporated into munitions, then enthalpic energy release is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent merges the manufacturing of energetic materials (aluminum) with high-density materials (tungsten or tantalum) into a single integrated thixotropic processing step. This combining of materials and processes creates a composite munitions material with enhanced enthalpic energy release while avoiding the need for separate manufacturing operations, thereby reducing overall manufacturing complexity despite the advanced material system.
3Volume of stationary object
If high-density materials are added to energetic materials, then bulk density equivalent to steel is achieved, but material heterogeneity increases
Solution Approach 1:
The patent utilizes thixotropic processing to control the physical state and flow characteristics of the composite material during manufacturing. By processing the aluminum-tungsten/tantalum composite in a semi-solid thixotropic state, the material can be formed with controlled microstructure that achieves bulk density equivalent to steel while maintaining compositional stability through the specific rheological properties of the thixotropic slurry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables fragment speeds up to twice that of conventional systems, with enhanced fragmentation and reactivity, overcoming limitations in shock loading and gas-dynamic expansion phases, and providing unique thermal and mass properties for structural applications.
Implementation Method 1
The process is named after the fluid property thixotropy, which is the phenomenon that allows this process to work. Simply, thixotropic fluids shear when the material flows, but thicken when standing.
Data Source
AI summary
The present inventions provide methods of manufacturing methods for case metallic materials for munitions that have high enthalpic energy release and controlled fragmentation and breakup enabling fragment speeds up to twice what is otherwise possible in explosively driven metal systems, and munitions made by such methods. Embodiments of the invention involve the thixotropic processing of energetic materials such as aluminum together with high density materials such as tantalum or tungsten to achieve material microstructures with a bulk density equivalent to steel, but with the energy release potential of materials such as finely dispersed aluminum powders. Such methods of mixing and blending of high energy and high density materials can provide a microstructure that has large density and shock impedance differences over length scales of 10-100 microns, resulting in enhanced materials fragmentation in the shock or brisant loading regime, incipient melting at the lower melting point constituents, and additional enhancement of fragmentation in the gas-dynamic expansion phase of munitions breakup. Additionally, the present inventions provide a range of surface and near-surface processing methods to enhance spall and ejecta from conventional munitions systems, enhancing munition breakup and reactivity as well.