Interface-controlled fatigue cracking of SCS-6/Ti-22Al-23Nb orthorhombic titanium aluminide composite
- Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering
The effect of aging at elevated temperature on interfacial stability and fatigue behavior of a SCS-6/Ti-22Al-23Nb orthorhombic (O) titanium aluminide composite is investigated. The composite was heat treated in vacuum at 900 C for up to 250 hours to change the microstructural characteristics. The stability of the matrix alloy and interfacial reaction zone after extended thermal exposure was analyzed. The effect of interface on fatigue behavior, including stiffness degradation, evolution of fatigue damage, and crack growth rates, was characterized. Finally, a modified shear-lag model was used to predict the saturated matrix crack spacing in the composite under fatigue loading. The results demonstrate that aging at elevated temperature affects the stability of the interfacial reaction zone, which, in turn, degrades the fatigue properties of the composite. However, fatigue crack will not developed from the ruptured interfacial reaction layer until the thickness of the reaction zone or the maximum applied stress exceeds a critical value.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 290257
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 29, Issue 11; Other Information: PBD: Nov 1998
- Country of Publication:
- United States
- Language:
- English
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