Date of Award
Doctor of Philosophy
Material Science and Engineering
Lawrence E. Murr
The issue is derived from ballistic erosion as it relates to nanoparticle production and respiration of these particles as a health concern ballistic erosion and ballistic erosion as it relates to railgun performance. A common thread between these two issues is dynamic recrystallization (DRX). DRX has been demonstrated to be the dominant mechanism for solid-state flow associated with ballistic projectile/target penetration and interaction, friction-stir welding phenomena, and other high-strain rate deformation phenomena.
Aerosol particulates collected on filters from ballistic penetration and erosion events for W-Ni-Co and W-Ni-Fe kinetic energy rod projectiles penetrating steel target plates were observed to be highly cytotoxic after 48 h exposure to human epithelial A549 lung cells. The aerosol consisted of micron-size Fe particulates and nanoparticulate aggregates consisting of W, Ni or W, Co and some Fe, characterized by SEM and TEM, and using energy-dispersive (X-ray) spectrometry by (EDS) for elemental analysis and mapping. Cytotoxic assays of micron and nano-size, manufactured metal particulates of W, Ni, Fe, and Co demonstrated that only the nanoparticulate elements demonstrated measurable cytotoxicity. Aluminum projectile (or armature) tribomaterial deposition onto copper conducting rails in an experimental solid-armature railgun system was observed, by optical, SEM and TEM. The extreme deformation at the aluminum/copper interface creates a solid-state flow regime by dynamic recrystallization which also leads to the erosion-product deposition. Melting of the low-temperature aluminum deposit also contributes to the rail damage and degradation of electromagnetic behavior. The creation of nano-grains by dynamic recrystallization allows for mixing at the aluminum/copper interface, and there is no evidence for traditional alloying.
Received from ProQuest
Brenda Ivette Machado
Machado, Brenda Ivette, "Ballistic Projectile Metallurgical Issues And Fundamentals: Aerosol Production In Rod Penetration Erosion And Erosion Phenomena Associated With Railgun Development" (2011). Open Access Theses & Dissertations. 2331.