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 DK_th fatigue thresholds are not substantially changed between 25° and 1100° C; however, there is a sharp decrease in DK_th at 1200^oC (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