TIN AS A SHOCK-MELTING BINDER FOR REACTIVE MATERIALS
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Authors
Esposito, Owen S.
Subjects
explosives
reactive materials
fragmentation
reactive materials
fragmentation
Advisors
Hooper, Joseph P.
Date of Issue
2020-06
Date
Publisher
Monterey, CA; Naval Postgraduate School
Language
Abstract
Reactive material warhead cases have the potential to greatly increase ordnance lethality by the addition of metal combustion, to explosive and fragmentation effects. Efficient combustion of the reactive metal relies on adequate dispersion of fine metal debris following detonation or impact. This thesis examines the use of tin as a soft binder for cold-isostatically pressed aluminum powder. The tin can potentially shock melt under rapid loading, increasing the dispersion of the aluminum by dynamically creating liquid failure regions. Several mechanical tests, including Split-Hopkinson Pressure Bar compression and Brazilian tension tests, gas gun impact tests, and three-point bend tests, as well as scanning electron microscopy, were used to determine dynamic strength, fragmentation properties, fracture toughness, and other mechanical properties of aluminum-tin composites of varying composition. Samples with lower tin content (5–10% by volume) were highly homogeneous and had low porosity following annealing. However, from a structural standpoint the tin binder results in reductions in strength and toughness compared to a pure pressed-aluminum powder compact. Analysis of the microstructure shows that tin acts as a soft buffer, weakening mechanical properties by preventing interlocking of the aluminum particles during the compaction. The final optimized composite may be useful for enhanced blast thermobaric cases that favor metal dispersion over structural strength.
Type
Thesis
Description
Series/Report No
Department
Physics (PH)
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NPS Report Number
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Distribution Statement
Approved for public release. distribution is unlimited
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.