Date of Award
Master of Science
Roy J. Schulz
Basil N. Antar, Ahmad D. Vakili
The purpose of this research is to evaluate, compare, and correlate the microstructure and mechanical properties of a selected group of ceramic armor samples to the V50 ballistic limit velocity. This study is to identify any relation between the desired material properties and the relevant microstructure parameters that significantly influence the ballistic limit velocity. The ceramic materials, silicon carbide and boron carbide, were produced and provided by five foreign companies. These companies were under contract by the United States Army, Research, Development, and Engineering Command to provide ceramic armor for comparative testing and material evaluation.
Ballistic testing was carried out to determine the V50 ballistic limit velocity for each ceramic material; mechanic testing of each ceramic material was performed to obtain material density, microindentation hardness, and flexural strength. Ceramography analysis of the material was also carried out to characterize the microstructure for each material.
Results showed that the ranges in these properties of the ceramic materials properties were determined as follows: Flexural strength ranged from 385 to 683 MPa, Knoop hardness ranged from 2,200 to 3258 kgf/mm2, density ranged from 3.1659 to 3.2376 g/cm3, grain size ranged from 5 to 15 μm, and porosity ranged from 2 to 10%. The ballistic limit velocities for these ceramic materials ranged from 292 to 372 m/s.
The ballistic limit velocity was well correlate with the ceramic flexural strength. Other material property such as density, microindentation hardness, and grain size did not directly correlate with the ballistic performance. The porosity of these ceramic materials did somewhat correlated with ballistic performance data dispersion or scatter, with increased scatter occurring at higher porosity levels.
As a note, the ballistic tests were done on the composite laminated ceramic but the material and microstructure properties in this study only refer to the ceramic materials. The front and backing fibrous material that comprised of the composite laminated ceramic was not considered in the material analysis of this study. It is my estimation and experience from testing and evaluating ballistic armor that the ceramic provides approximately 90% to 95% in the erosion process and breaking up the steel core projectile. The fibrous material accounts for approximately 5% to 10% in stopping residual fragments and absorbing the kinetic energy. Therefore, the main focus was on the ceramic properties influence on V50 ballistic limit.
McDonald, Adolphus, "A Study of Material Properties and Relevant Microstructure Parameters that May Influence the V50 Ballistic Limit Velocity of Composite Ceramics. " Master's Thesis, University of Tennessee, 2005.