Chapter 21. Pre-Impact Damage Assessment of Dra Metal Matrix Composite Encapsulated Sic Ceramics
- Hua-Tay Lin,
- Mrityunjay Singh
Published Online: 26 MAR 2008
Copyright © 2002 The American Ceramic Society
26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3
How to Cite
Wells, J.M., Green, W.H. and Rupert, N.L. (2008) Pre-Impact Damage Assessment of Dra Metal Matrix Composite Encapsulated Sic Ceramics, in 26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 23, Issue 3 (eds H.-T. Lin and M. Singh), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294741.ch21
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 2002
Print ISBN: 9780470375785
Online ISBN: 9780470294741
Encapsulation of monolithic ceramic materials is one concept for confinement of candidate armor ceramic materials which enables both constraint during ballistic impact and retention of damage fragments for post-impact evaluation by either destructive or non-destructive methods. Non-destructive examination is essential for the pre-impact baseline characterization of consolidated samples, which subsequently will be tested bailistically and then further characterized for damage in the post-impacted condition. Such non-destructive characterization of experimental samples of SiC ceramic tile material encapsulated within discontinuously reinforced aluminum metal matrix composite, DRA, was conducted using x-ray computed tomography, CT. Each sample consisted of one 10 cm × 10 cm × 1.2 cm thick SiC ceramic tile encapsulated with 356/ SiCp/60v%DRA forming a test sample of 15.2 cm × 15.2 cm × 5.3 cm thick overall dimensions. Both digital x-ray radiography and computed tomography were performed on the samples using a custom built ACTIS 600/420 x-ray computed tomography scanner front Bio-Imaging Research, Inc., to characterize and document the “as fabricated” samples prior to planned ballistic testing.
Results of three samples fabricated by the pressure infiltration casting process indicated pre-existing voids in the MMC encapsulant material and substantial multiple cracks in both the MMC and the SiC materials. Such defects in the as-fabricated samples, had they gone undetected, would have been difficult to separate from later anticipated ballistically-induced damage. Also, significant displacement of the SiC tile was detected indicating an undesired repositioning of the SiC tile during the encapsulation casting step. A subsequent sample fabricated by a presssureless metal infiltration process revealed significantly less extensive cracking than observed in the previous samples. This paper discusses the application of x-ray computed tomography (XCT) to pre-impact characterization of encapsulated ceramic target materials.