Mechanical Properties for Advanced Engine Materials

The experimental evaluation of advanced mechanical properties that characterize the behavior of emerging materials for aerospace structures under a broad range of conditions representative of those encountered in service was emphasized in this investigation. The information guided the development of life prediction methodologies which are based on the concept of damage tolerance as a design philosophy. The research effort was subdivided into four interrelated tasks: (a) material characterization tests, (b) experimental procedure and test developments, (c) analytical and modeling developments, and (d) test support activities and data archival. Material characterization tests for fatigue, creep, and crack growth responses were conducted on a titanium matrix composite reinforced with continuous SiC fibers and fabricated from a foil-fiber-foil layup. The molybdenum wire used in the weaving of the fiber mats was a major factor in the development of damage under fatigue and creep test conditions. A model ceramic matrix composite composed of an aluminosilicate glass matrix and SiC fiber tows provided some interesting fatigue and fracture toughness responses. Behavior of monolithic materials were evaluated under creep, creep crack growth, fatigue crack growth, and oxidation conditions. Significant developments in test procedures and systems have been accomplished with emphasis on conducting thermomechanical fatigue (TMF) tests.