Production of functionally graded materials from electrochemically modified carbon preforms

A new process based on carbon as a precursor material has been applied succ essfully to the production of graded Al2O3/Al composites. For this purpose, distinct porosity gradients were introduced into carbon materials via anod ic oxidation, The graded structure of the carbon preforms was replicated us ing two subsequent infiltration steps to yield fully dense Al2O3/Al functio nally graded materials with an interpenetrating network microstructure and a continuous variation of metal content.