William Guy Clark

Nondestructive characterization of material properties of metal-matrix composites

Abstract In this investigation, nondestructive evaluation (NDE) was conducted on silicon carbide particulate (SiCp) reinforced aluminum (Al) metal-matrix composite products at various processing stages, including raw powders, powder mixtures and final product extrusions. In NDE of powders, the eddy current is effective in identifying the matrix powder alloy chemistry and particle size, and in evaluating the mix ratio of SiC p in Al matrix alloy powders. In NDE of composite extrusions, ultrasonic techniques were employed to determine the anisotropic stiffness constants of composite extrusions. The moduli measured by ultrasonics were found to be in good agreement with those obtained by tensile testing. Multiple NDE methods (e.g., eddy current and ultrasonics) can be utilized to characterize the material properties of composite products at different processing stages. These results suggest that NDE techniques can be incorporated into the manufacturing processes of metal-matrix composites to provide on-line, closed-loop control of fabrication variables.