NDE METHODS FOR MICROSTRUCTURAL CHARACTERIZATION OF METAL-MATRIX COMPOSITES

THE USE OF COMPOSITE MATERIALS HAS GROWN SIGNIFICANTLY IN THE PAST DECADE. THESE MATERIAL SYSTEMS ARE BEING USED AS CRITICAL COMPONENTS IN INCREASINGLY COMPLEX STRUCTURES. METAL-MATRIX COMPOSITES, MORE SPECIFICALLY, ARE BEING CONSIDERED FOR APPLICATIONS FROM TURBINE ENGINES TO PRIMARY AIRCRAFT STRUCTURES. THEIR INTEGRITY IN THESE STRUCTURES MUST BE INSURED IN ORDER FOR THE ADVANTAGES OF METAL-MATRIX COMPOSITES TO BE FULLY REALIZED. THE FIBER-MATRIX INTERFACEREACTION ZONE AND THE RESIDUAL STRESS STATE OF METAL-MATRIX COMPOSITES ARE TWO PARAMETERS WHICH ARE DIFFICULT TO MEASUREAND WHICH DETERMINE, TO A GREAT EXTENT, THE STRENGTH AND LIFETIME OF THESE MATERIALS. DUAL-ENERGY MICROTOMOGRAPHY ISPROPOSED AS AN INNOVATIVE METHOD TO NON-DESTRUCTIVELY INVESTIGATE THE FIBER-MATRIX REGION. THE PROPOSED STUDY WILL REVIEW CURRENT UNDERSTANDING OF THE CHARACTERISTICS OF THE FIBER-MATRIX INTERFACE AND THE RESIDUAL STRESS STATE OF METAL-MATRIX COMPOSITES AND EXPERIMENTALLY EVALUATE THE FEASIBILITY OF DUAL-ENERGY MICROTOMOGRAPHY TO NON-DESTRUCTIVELY MEASURE THESE CHARACTERISTICS. DESIGN SPECIFICATIONS AND A CONCEPTUAL DESIGN WILL ALSO BE COMPILEDFOR A COMPLETE NON-DESTRUCTIVE TOMOGRAPHIC MICROSTRUCTURAL IMAGING SYSTEM FOR METAL-MATRIX COMPOSITES FOR FUTURE PHASE II DEVELOPMENT.