Tin as a Shock-Melting Binder for Reactive Materials
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 (510% 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2020
- Accession Number
- AD1114553
Entities
People
- Owen S. Esposito
Organizations
- Naval Postgraduate School