Damage Evolution in Creep of SCS-6/Ti--24Al--11Nb Metal-Matrix Composites

• Published in: Journal of reinforced plastics and composites 1991-10, Vol.12 (3), p.296-310
• Main Author: Khobaib, M
• Format: Article
• Language: English
• ISSN: 0731-6844

Titanium aluminide composites reinforced with SiC fibers belong to a family of an emerging class of new materials suited for advanced aerospace structural application. However, these materials are yet to be characterized for elevated temperature mechanical behavior and their failure mechanism. During flight, the structural components of advanced aircraft undergo sustained loading for extended periods of time. These materials must show satisfactory creep resistance before they can be recommended for actual use. This investigation deals with the experimental study of creep behavior of a model SCS-6/Ti--24Al--11Nb composite. The main objective is to understand the damage evolution under sustained load at high temperature in this class of material. Tensile creep tests were conducted over the temperature range of 650-815 deg C. All the tests were conducted in laboratory air on specimens fabricated from unidirectional panels. The specimens were loaded with tensile axis parallel to (0) fiber. The strain vs. time plot produced a classical creep behavior with three distinct regions. The total creep strain to failure was found to be less than the strain for fiber failure. Evidence of fiber failure was observed as early as in the initial part of the secondary stage.