Paper number 883

ON TRANSVERSE FRACTURE MECHANISMS OF 1140+/TI-6AL-4V AND SCS-6/TI ▀21S COMPOSITES UNDER TENSILE LOADING

X. Wu1, H.Mori2 and P. Bowen1

1School of Metallurgy and Materials, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
2Research Centre for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153, Japan

Summary The transverse behaviour of 1140+/Ti-6Al-4V and SCS-6/Ti ▀21s composites has been investigated by tensile tests in air and in situ within a FEG-SEM using direct observations. Acoustic Emission Analysis(AE) has also been used to assess and locate positions of damage. It has been observed that debonding in both composites can start at very low stresses due to defects and/or undulations at interfaces. AE events can be found almost immediately on loading during premature debonding of SCS-6/Ti ▀21s, but few for the 1140+/Ti-6-4 composite. Many AE events of high energies were detected in the region of the first knee on stress ~ time curves. The peak energies of AE obtained in 1104+/Ti-6-4 and SCS-6/Ti ▀21s are of ~150 and ~650ÁJ, respectively. Cracking of carbon coatings and/or reaction zones also produce distinct AE events. Distinct differences in AE behaviour have been found between 1140+/Ti-6-4 and SCS-6/Ti ▀21s composites.
Keywords transverse tensile loading, AE behaviour, in situ observation, debonding.

Theme : Metal Matrix Composites ; Microstructure/Properties Relationship

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