Investigation of mechanical properties of chemically vapor infiltrated ceramic matrix composites under pure tension

Vapor phase synthesis is emerging as a method for the preparation of near final-shape, ceramic matrix composites (CMCs) for advanced structural applications. Mechanical properties have been investigated in pure tension at room temperature, 1000°C, and at room temperature after exposure to thermal shock, and after oxidation for the Nicalon/SiC CMCs fabricated by forced chemical vapor infiltration (FCVI) and isothermal chemical vapor infiltration (ICVI). Due to the short length of the specimens fabricated by the FCVI method, there is a need for an innovative precision alignment in tensile tests for this material. In addition, there is also a need to evaluate the properties of FCVI and ICVI composites under identical conditions for an effective comparison. The approaches considered for the tensile testing of short specimens are presented in this paper. Some of the initial test results for these composites are also given.