CERAMIC COMPOSITE INTERFACES 2 Uncoated Increasing Coatin Thickness 6070 COD (um) Figure 3 Force-displacement curve for pullout testing of four SiC-glass composites with carbon erlayers of increasing thickness(from 16) sliding and attributed it to the reduction in residual stress with fiber loading Alternatively, compliant interphase layers of varying thicknesses also can serve to accomodate large residual thermal mismatch stresses (22, 23) MEASURING INTERFACE PROPERTIES Over the past fifteen years, a variety of interfacial tests for ceramic compos ites either have evolved from evaluation methods used in the polymer-matrix composite field or have developed anew for brittle-brittle composites. Shown in Figure 4 is a sampling of tests for the mechanical evaluation of interfaces (24, 25). Of the tests shown, the bimaterial bend test( Figure 4a), the bimaterial cantilever beam test( Figure 4e ), the single-edge notch beam test(Figure 4), the Brazilian disk test( Figure 4g), the double-cleavage drilled compression tests (Figure 4h), the vickers indentation test(Figure 4)), and Hertzian indentation tests(Figure 4) are occasionally used in screening tests to ascertain whetherP1: ARK/MBL/rkc P2: MBL/vks QC: MBL/agr T1: MBL May 16, 1997 13:47 Annual Reviews AR034-16 CERAMIC COMPOSITE INTERFACES 505 Figure 3 Force-displacement curve for pullout testing of four SiC-glass composites with carbon interlayers of increasing thickness (from 16). sliding and attributed it to the reduction in residual stress with fiber loading. Alternatively, compliant interphase layers of varying thicknesses also can serve to accomodate large residual thermal mismatch stresses (22, 23). MEASURING INTERFACE PROPERTIES Over the past fifteen years, a variety of interfacial tests for ceramic compos￾ites either have evolved from evaluation methods used in the polymer-matrix composite field or have developed anew for brittle-brittle composites. Shown in Figure 4 is a sampling of tests for the mechanical evaluation of interfaces (24, 25). Of the tests shown, the bimaterial bend test (Figure 4a), the bimaterial cantilever beam test (Figure 4e), the single-edge notch beam test (Figure 4f ), the Brazilian disk test (Figure 4g), the double-cleavage drilled compression tests (Figure 4h), the Vickers indentation test (Figure 4i), and Hertzian indentation tests (Figure 4j) are occasionally used in screening tests to ascertain whether