Advanced Pressure Infiltration Casting of Thick Section Al Matrix Composites for Armor Applications

Proposed here is a method by which large area, thick sectioned, whisker and particulate reinforced, aluminum matrix composites may be produced for lightweight armor applications. The first objective of this work is to conduct preliminary process optimization producing reinforced specimens 6" by 6" by 1" thick. Aluminum alloys 5083 and 224.2 will be infiltrated into SiC whiskers, alumina particulate, and whisker/particulate preforms. Reinforcement loading will vary between 10 and 55 volume fraction. Specimens with graded volume fraction will also be produced. Material characterization will include tensile testing, microstructural evaluation, and ballistic testing to determine the most promising alloy-reinforcement combinations for further examination. Concurrently, with the first objective, the second objective of this work is to adapt a 30" diameter by 5" long pressure infiltration apparatus capable of casting 18 composite parts, 12" by 12" by 2" thick in a single run. After promising materials are identified and the large pressure vessel is ready, at least 6 parts of at least 12" by 12" by 2" thick will be delivered for ballistic evaluation. The final objective of this work will be to demonstrate that these large section composites may be produced at low cost.