K. Shirato 1, D. Chen 1, M. W. Barsoum 2, T. El-Raghy 2, and R. O. Ritchie 1

1 Materials Sciences Division, Lawrence Berkeley National Laboratory, and Department of Materials Science and Engineering, University of California, Berkeley, CA 74720
2 Department of Materials Engineering, Drexel University, Philadelphia, PA 19104

The cyclic fatigue behavior of reactive hot-pressed Ti3SiC2 ceramics are examined at temperatures from ambient to 1200° C with the objective of characterizing the high-temperature mechanisms controlling crack growth. Comparisons are made of two monolithic Ti3SiC2 materials with fine- (3-10 m m) and coarse-grained (70-300 m m) microstructures. Results indicate that the DKth fatigue thresholds are not substantially changed between 25° and 1100° C; however, there is a sharp decrease in DKth at 1200oC (above the "ductile-brittle" transition temperature), where significant high-temperature deformation and damage are first apparent. Of the two microstructures, the coarse-grained Ti3SiC2 exhibits substantially higher cyclic-crack growth resistance at both ambient and elevated temperatures. This results from an enhanced effect in the coarser grained microstructure of crack bridging in the crack wake from both grains and lamellae within grains, and from the correspondingly more tortuous crack path.

Full Text in PDF form: TMS Conference presentation in Fall 2000

Fatigue-crack growth and fracture properties of coarse and fine-grained Ti 3 SiC 2 by C.J. Gilbert, D.R. Bloyer, M.W. Barsoum, T. El-Raghy, A.P. Tomsia and R.O. Ritchie. Scripta Materialia, 2000

Cyclic Fatigue-Crack Growth and Fracture Properties in  Ti3SiC2Ceramics at Elevated Temperatures by D. Chen, K. Shirato, M. W. Barsoum, T. El-Raghy, and R. O. Ritchie, Journal of the American Ceramic Society, vol.84 (12), Dec. 2001, pp. 2914-2920

LBNL , MSD * Ritchie Group * Dept of MSME , UC Berkeley
last updated 08-03