Nondestructive Characterization for Metal-Matrix Composite Fabrication
SourceNondestructive characterization has been performed on composite products at different stages of fabrication processes including raw powders, powder mixtures, billets, and final product extrusions. Eddy current was found to be effective in identifying matrix powder alloy chemistry and particle size, and in determining the mix ratio of silicon carbide (SiC) reinforcement particles in aluminum matrix alloy powders. Ultrasonic techniques were capable of identifying SiC clusters in large-scale, consolidated powder metallurgy (P/M) metal-matrix composite (MMC) billets, while eddy-current methods could be used to determine near-surface density variations in the billets. Multiple nondestructive evaluation (NDE) techniques (eddy current, ultrasonics, and resistivity) could be employed to quantify microstructural characteristics of composite extrusions. These results indicate that NDE methods can be integrated into manufacturing processes to provide on-line, closed-loop control of fabrication parameters.