Accession Number : ADA302118

Title :   Hybrid Ceramic Matrix Composites: A Study of Transverse Properties and Failure Modes.

Descriptive Note : Final technical rept. Apr 93-Aug 95,

Corporate Author : MISSOURI UNIV-ROLLA

Personal Author(s) : Dharani, L. R. ; Carroll, D. R.

PDF Url : ADA302118

Report Date : 31 OCT 1995

Pagination or Media Count : 111

Abstract : The purpose of this study was to demonstrate the effects, and ultimately, the advantages of forming a hybrid ceramic matrix composite (HCMC) by adding whiskers to a fiber reinforced ceramic matrix composite (FCMC). The addition of whiskers to a continuous fiber ceramic composite has been shown to produce a hybrid composite that: (1) is more stiffer, (2) resists microcracking until higher loading levels, (3) has improved transverse strength and stiffness and (4) shows improved damage tolerance when compared with fiber reinforced composites (FCMC). The modulus was found to be, on average, 212 + or - 24 GPa for the hybrid system compared to 170 + or - 20 GPa for the FCMC system. The ultimate strength was basically preserved, but the stress at which microcracking was first observed was increased for the hybrid system to 121.4 + or - 19.0, an increase almost threefold over the FCMC system. The transverse microcracking stress was 31.0 + or - 7.0 MPa for the HCMC compared with 16.4 + or - 1.0 MPa for the FCMC. The ultimate strengths were 62.4 + or - 7.0 MPa and 24.2 + or - 6.0 MPa, respectively. The study has indeed demonstrated the benefits from hybridization of ceramic composites and provide a basis for further study. (MM)

Descriptors :   *CERAMIC MATRIX COMPOSITES, *FIBER REINFORCED COMPOSITES, *CERAMIC MATERIALS, *WHISKER COMPOSITES, STRESS STRAIN RELATIONS, DENSITY, DAMAGE, COMPOSITE MATERIALS, LAMINATES, STIFFNESS, MODULUS OF ELASTICITY, THESES, FABRICATION, HOT PRESSING, TOUGHNESS, POROSITY, STRENGTH(MECHANICS), FRACTURE(MECHANICS), HEAT TREATMENT, FRACTOGRAPHY, HYBRID SYSTEMS, TOLERANCES(MECHANICS), FAILURE(MECHANICS), ACOUSTIC EMISSIONS, SILICON CARBIDES, TRANSVERSE, MICROCRACKING.

Subject Categories : Ceramics, Refractories and Glass
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE