EFFECT OF MATRIX ALLOY ON LONGITUDINAL TENSILE BEHAVIOUR OF FIBRE REINFORCED TITANIUM MATRIX COMPOSITES

• Published in: Scripta materialia Vol. 37; no. 12; pp. 1855 - 1862
• Main Authors: Thomas, M.P, Winstone, M.R
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Ltd 15-12-1997; Elsevier Science
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fatigue, corrosion fatigue, embrittlement, cracking, fracture and failure; Fatigue, embrittlement, and fracture; Materials science; Metals. Metallurgy; Physics; Treatment of materials and its effects on microstructure and properties; Fibre reinforced metal; Tensile tests; Mechanical properties; Silicon carbides; Mechanical tests; Experimental study; Titanium base alloys; Tensile strength; Young modulus; Composite materials; Temperature effects; Stiffness; Fractography; Tensile properties; Turbines
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/S1359-6462(97)00379-5

The MMCs consist of an IMI 318 (Ti-6Al-4V) matrix or an IMI 834 (Ti-5.8Al-4.0Sn-3.5Zr-0.7Nb-0.5Mo-0.35Si-0.06C) matrix reinforced with SM 1140+ carbon coated SiC fibre. The mechanical properties of the two MMCs are not significantly different because of the dominance of the fibre properties over those of the matrix alloy. MMC yielding at ambient temperature appears to be due to matrix yield, whilst at 600 deg C there are two yield points, due to matrix yielding at low strains and fibre failure at high strains. Failure of SM1140+ fibre initiates at the tungsten core/SiC interface, with fibre coating and reaction product failure occurring in the final stages of fibre fracture. The MMCs exhibit different interfacial failure modes. IMI 318/SM1140+ fails along the SiC/carbon boundary, while IMI 834/SM1140+ fails at the carbon /TiC interface. IMI 834/SM1140+ is more susceptible to oxidation damage at 600 deg C than IMI 318/SM1140+. Brittle cleavage occurs in the IMI 834 matrix between closely spaced fibres. This may be a result of the combination of carbon embrittlement, high residual stress and matrix constraint.