UNIDIRECTIONAL TENSILE STRESS-STRAIN RESPONSE OF BP-SIC FIBER-REINFORCED TI-6AL-4V

The BP C/TiB2 coated SiC fiber reinforced Ti-6Al-4V composite has been studied experimentally and analytically. A good understanding of the material's room temperature mechanical properties has been achieved. T he tests include longitudinal tension and transverse tension with both monotonic loading and cyclic loading cases. Micromechanical models ha ve also been developed and give good correlation with test results for longitudinal and transverse tension. Loading-unloading-reloading test s enabled the interfacial strength to be determined. The transverse cy clic loading case was modeled and the friction coefficient at the fail ed interface was evaluated. In addition, the effect of the C/TiB2 coat ing on the transverse tensile properties was studied. The low stiffnes s carbon with anisotropic thermal properties reduced the interfacial r adial residual stresses, and therefore decreased the composite stress at interfacial debonding. The composite transverse modulus was also re duced by the coating. Possible ways of improving the material properti es are considered.