EFFECTS OF STRESS CONCENTRATORS ON DAMAGE EVOLUTION IN SIC/SIC COMPOSITES

Non-oxide ceramic matrix composites (CMCs) are currently being investigated for high temperature applications. Geometric induced redistribution of stress is an important factor in determining the mechanical performance of engineered materials, and understanding of it is necessary for their ultimate implementation as components. Towards this understanding, several melt infiltrated SiC/SiC coupons of different notch configurations, but similar constituents, were tested in tension with modal acoustic emission. Accurate stress-dependent damage locations were determined and compared with destructive fractography, revealing complicated damage morphology and allowing for comparison of traditional un-notched coupons. Similarly, accurate location analysis, in conjunction with precise microscopy, can provide for a deeper insight in the relationship between acoustic emission and fracture processes in CMCs.