The transverse behavior of 1140+/Ti-6-4 and SCS-6/Ti-β21s composites has been investigated using conventional tensile testing in air. Acoustic emission (AE) has also been used to assess and to locate the position of damage. Few AE events can be detected in 1140+/Ti-6-4 composites below the stress of ∼250 MPa, whereas for SCS-6+/Ti-β21s composites, AE events are found almost immediately on loading. Many AE events of high energy were detected over a range of stresses, which appear to be associated with debonding. Continuous AE events are obtained with an increase of stress, and this suggests that debonding is an incremental process: a ring crack (formed by premature debonding at the surface) penetrates into the depth along interface "tubes." The peak energy of AE events obtained in SCS-6/Ti-β21s composites is ∼650 arbitrary units, which is approximately 4 times that obtained in 1140+/Ti-6-4 composites. Distinct AE events have also been deduced to correspond to cracking of carbon coating layers and fiber/matrix reaction products. A change of fiber volume fraction from 8 to 21 pct for the 1140+/Ti-6-4 composites has no effect on the characteristics or distribution of AE events received.
|Number of pages||9|
|Journal||Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science|
|Publication status||Published - 1 Jan 2001|