ENVIRONMENTS

METAL MATRIX COMPOSITES ARE FABRICATED FROM HIGH STRENGTH FIBER OR PARTICLE REINFORCEMENTS AND A SUITABLE MATRIX ALLOY. ALUMINUM COMPOSITES HAVE SHOWN HIGH STRENGTH AND STABILITY AND ARE WELL SUITED TO ADVANCED MILITARY AND CIVIL DESIGN CONCEPTS. REINFORCING FIBERS OFTEN REACT WITH THE MATRIX ALLOY DURING FABRICATION AND PROCESSING FORMING A THIN DIFFUSION REACTION ZONE SURROUNDING THE REINFORCEMENT. THREE SEPARATE CORROSION REGIONS ARE THEN PRESENT IN THE COMPOSITE: FIBER, INTERDIFFUSION LAYER AND MATRIX ALLOY. TO STUDY THESE PHENOMENA, ALUMINUM METAL MATRIX COMPOSITES WILL BE HEAT TREATED TO ESTABLISH GROWTH OF THE INTERDIFFUSION LAYER FOR SEVERAL REINFORCING FIBERS INCLUDING GRAPHITE AND SILICON CARBIDE. THE CORROSION SUSCEPTIBILITY OF TREATED AND UNTREATED SAMPLES WILL BE COMPARED WITH THE MATRIX ALLOY. SHORT TERM EXPOSURE TESTS AND POTENTIODYNAMIC EVALUATIONS WILL BE CONDUCTED. THE EFFECT OF INTERDIFFUSION LAYER THICKNESS WILL ALSO BE CORRELATED WITH CORROSION SUSCEPTIBILITY OF THE COMPOSITE SAMPLE IN AQUEOUS CHLORIDE ENVIRONMENTS.