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Title: Effects of reaction layer on interfacial shear properties and strength of fiber in silicon-carbide (SiC) fiber-reinforced titanium alloy composite

Conference ·
OSTI ID:536380
 [1];  [2]; ;  [3]
  1. Univ. of Tokyo (Japan). Inst. of Industrial Science
  2. National Research Inst. for Metals, Tokyo (Japan). Failure Physics Div.
  3. Mitsubishi Heavy Industries, Ltd., Nagoya (Japan)

The effect of the interfacial thickness of the reaction layer on the interfacial shear properties and the tensile strength of double carbon-coated SCS-6 SiC fiber in Ti-15Mo-5Zr-3Al alloy matrix composite was examined. The major reaction layer thickness, that is, titanium-carbide (TiC) layer thickness, varied with heat-exposure temperature and time, respectively, and the resultant mean thickness of the reaction layer of the composite ranged from 0.4 to 1.7 {micro}m. The critical interfacial toughness, G{sub i}{sup c}, and the mean shear sliding resistance, {tau}{sub s}, were evaluated by the thin specimen pushout technique. Tensile strength of the silicon-carbide (SiC) fiber extracted from the titanium alloy matrix before and after the heat exposure was determined in relationship to the thickness of the reaction layer. The critical interface toughness, G{sub i}{sup c}, for the failure of the root of the reaction layer was {approx}4 J/m{sup 2}, and the average shear sliding resistance of the interface, {tau}{sub s}, was 102 to 118 MPa. The interfacial shear mechanical properties were adequate to prevent failure of the fiber due to the stress concentration caused by cracks that formed first in the reaction layer. The results showed that when the growth of reaction layer was within 1.7 {micro}m, the mean strength of the extracted fiber was unaffected by the existence of the reaction layer because of weak bonding between it and the fiber. However, with the increase of the reaction layer thickness, the strength distribution of the extracted fiber tended to Weibull bimodal distribution.

OSTI ID:
536380
Report Number(s):
CONF-940399-; ISBN 0-8031-2039-7; TRN: IM9745%%219
Resource Relation:
Conference: Life prediction methodology for titanium matrix composites symposium, Hilton Head, SC (United States), 22-24 Mar 1994; Other Information: PBD: 1996; Related Information: Is Part Of Life prediction methodology for titanium matrix composites; Johnson, W.S.; Larsen, J.M.; Cox, B.N. [eds.]; PB: 632 p.; ASTM special technical publication, 1253
Country of Publication:
United States
Language:
English