M.B. Ruggles-Wrenn et al /Composites Science and Technology 66(2006)2089-2099 5.2. Creep-rupture behavior everal ceramic-matrix composites. J Am Ceram Soc 2003;86(8:1282-91 The creep-rupture behavior of the N610/M/A ceramic 3]Prewo KM, Batt JA. The oxidative stability of carbon fibre reinforced composite was characterized for stress levels ranging from trix composites. J Mater Sci 1988: 23: 523-7 60 to 150 MPa at 900C. and for stress levels ranging from [4]Mah T Hecht NL, McCullum DE, Hoenigman JR,Kim HM. Katz AP, et al. Thermal stability of sic fibres(Nicalon). J Mater Sci 40 to 120 MPa at 1100C Creep tests of the uncoated fiber 984:19:1191-201. Nextel 610/Alumina composite were conducted at 900oC []More KL, Tortorelli PF, Ferber MK, Keiser JR. Observations of for 73 and 80 MPa accelerated silicon carbide recession by oxidation at high water-vapor pressures. J Am Ceram Soc 2000: 83(1): 211-3. At 1100C, the N610/M/A composite exhibits primary, 6 More KL, Tortorelli PF, Ferber MK, Walker LR, Keiser JR, condary and tertiary creep regimes. Creep strain accumu- Brentnall WD, Miralya N, Price JB. Exposure of ceramic and lation decreases with increasing applied stress. For all stress ceramic-matrix composites in simulated and actual combustor envi- levels investigated, the accumulated creep strain signifi ronments. In: Proceedings of international gas Turbine and aero. cantly exceeds the failure strain obtained in the tension test space Congress, 1999. Paper No. 99-GT-292 At 900C, short primary creep rapidly transitions into sec- [7 Ferber MK, Lin HT, Keiser JR. Oxidation behavior of non-oxide ceramics in a high-pressure, high-temperature steam environment. In ondary creep, no tertiary creep is observed. Creep strains Mechanical, thermal, and environmental testing and performance of are an order of magnitude lower than the failure strain eramic composites and components. In: Jenkins MG. Lara-Curzio obtained in tension test. Creep strains produced at 900C E, Gonczy ST, editors. ASTM STP, Vol 1392. American Society for are at least an order of magnitude lower than those Testing and Materials: 2000. P. 210-5 obtained at ll00°C [8] Haynes JA, Lance MJ, Cooley KM, Ferber MK, Lowden RA, Stinton DP CVD mullite coatings in high-temperature, high-press At 1100C, creep strain rates of N610/M/A range from air-H,O. J Am Ceram Soc 2000: 83(3): 657-9. 1. 4x 10 to 7.9x 10s. Furthermore, creep rates of [9] Opila EJ. Hann Jr RE Paralinear oxidation of sic in water vapor. J N610/M/A are what may be expected from Nextel 610 Am Ceram Soc1997;80(1):197-205 fibers alone. The relationship between the minimum creep [10] Opila EJ. Oxidation kinetics of chemically vapor deposited silicon carbide in wet oxygen. J Am Ceram Soc 1994: 77(3): 730-6 rate and applied stress can be represented by a power [11] Opila EJ Variation of the oxidation rate of silicon carbide with water law. The stress exponent (n a 3.5)is approximately equal sure. J Am Ceram Soc 1999: 82(3): 625-36 to that of the Nextel 610 fibers. The creep rates of the [12] Hermes EE, Kerans RJ. Degradation of non-oxide reinforcement and N610/M/A cross-ply are about an order of magnitude oxide matrix composites. Mat Res Soc, Symp Proc 1988: 125: 73-8 higher than those reported for N610/AS, a CMC rein [13] Szweda A. Millard ML, Harrison MG. Fiber-reinforced ceramic- forced with an eight-harness satin weave of Nextel 610 matrix composite member and method for making, US Pat. No 5 601 674.1997 fibers. Fiber weave architecture may be one of the factors [14] Sim SM, Kerans RJ. Slurry infiltration and 3-D woven composites affecting the creep response of the composite. Creep strain Ceram Eng Sci Proc 1992: 13(9-10): 632-41 rates of N610/M/a decrease significantly with decreasing [15] Moore EH, Mah T, Keller KA. 3D composite fabrication through At 900C, for creep stress levels belo matrix slurry pressure infiltration. Ceram Eng Sci Proc 150 MPa, creep rates of both N610/A and N610/M/A are [16 Lewis MH, Cain MG Doleman P Razzell AG, Gent Development At 150 MPa, creep rate of N610/M/A of interfaces in oxide and silicate matrix composites. In: Evans AG increases to 14×10-7s Naslain RG, editors. High-temperature ceramic-matrix composites At 900C the uncoated fiber composite did not Il: manufacturing and materials development. American Ceramic a run-out For N610/M/A the run-out stress was I Society:1995.p.4-52. (67% UTS). The addition of a monazite coating [17] Lange FF, Tu wC, Evans AG. Processing of damage-toler oxidation-resistant ceramic matrix composites by a precursor cantly improved the creep resistance, presumably by pre- tration and pyrolysis method. Mater Sci Eng A 1995: A195: 145-50 venting fiber/matrix bonding and allowing fiber pullout. [18] Underberg R, Eckerbom L. Design and processing of all-oxide The run-out N610/M/A specimens retained over 90% of composites. In: Evans AG, Naslain RG, editors. High-temperature tensile strength. At 1100oC. run-out was not achieved cramic-matrix composites i: manufacturing and materials develop- ment. American Ceramic Society: 1995. p 95-104 [19] Mouchon E, Colomban P. Oxide ceramic matrix/oxide fiber woven Acknowledgements fabric composites exhibiting dissipative fracture behavior. Compos ites I995:26:175-82 The authors would like to thank Dr. R.A. Kerans and [0] Morgan PED, Marshall DB. Ceramic composites of monazite and Dr. T. Parthasarathy for many valuable discussie 21]Tu wC, Lange FF, Evans AG. Concept for a dama ceramic composite with strong interfaces. J Am Ce References [22]Kerans R, Hay RS, Pagano NJ, Parthasarathy TA. The role of the [] Verrilli M, Opila EJ, Calomino A, Kiser JD. Effect of environment 1989:68(2):429-42. on the stress-rupture behavior of a carbon-fiber-reinforced silicon [23] Evans AG, Zok FW. Review: the physic carbide ceramic m 2004;87(8):1536-42. [24] Kerans RJ, Parthasarathy TA Crack def [2] Zawada LP, Staehler J, Steel S. Consequence of intermittent exposure ites and fiber coating design criteria. Composites: Part A to moisture and salt fog on the high-temperature fatigue durability of 199930:521-45.2. Creep-rupture behavior The creep-rupture behavior of the N610/M/A ceramic composite was characterized for stress levels ranging from 80 to 150 MPa at 900 C, and for stress levels ranging from 40 to 120 MPa at 1100 C. Creep tests of the uncoated fiber Nextel 610/Alumina composite were conducted at 900 C for 73 and 80 MPa. At 1100 C, the N610/M/A composite exhibits primary, secondary and tertiary creep regimes. Creep strain accumu￾lation decreases with increasing applied stress. For all stress levels investigated, the accumulated creep strain signifi- cantly exceeds the failure strain obtained in the tension test. At 900 C, short primary creep rapidly transitions into sec￾ondary creep, no tertiary creep is observed. Creep strains are an order of magnitude lower than the failure strain obtained in tension test. Creep strains produced at 900 C are at least an order of magnitude lower than those obtained at 1100 C. At 1100 C, creep strain rates of N610/M/A range from 1.4 · 106 to 7.9 · 105 s 1 . Furthermore, creep rates of N610/M/A are what may be expected from Nextel 610 fibers alone. The relationship between the minimum creep rate and applied stress can be represented by a power law. The stress exponent (n 3.5) is approximately equal to that of the Nextel 610 fibers. The creep rates of the N610/M/A cross-ply are about an order of magnitude higher than those reported for N610/AS, a CMC rein￾forced with an eight-harness satin weave of Nextel 610 fibers. Fiber weave architecture may be one of the factors affecting the creep response of the composite. Creep strain rates of N610/M/A decrease significantly with decreasing temperature. At 900 C, for creep stress levels below 150 MPa, creep rates of both N610/A and N610/M/A are less than 108 s 1 . At 150 MPa, creep rate of N610/M/A increases to 1.4 · 107 s 1 . At 900 C the uncoated fiber composite did not achieve a run-out. For N610/M/A the run-out stress was 120 MPa (67% UTS). The addition of a monazite coating signifi- cantly improved the creep resistance, presumably by pre￾venting fiber/matrix bonding and allowing fiber pullout. The run-out N610/M/A specimens retained over 90% of tensile strength. At 1100 C, run-out was not achieved. Acknowledgements The authors would like to thank Dr. R.A. Kerans and Dr. T. Parthasarathy for many valuable discussions. References [1] Verrilli MJ, Opila EJ, Calomino A, Kiser JD. Effect of environment on the stress-rupture behavior of a carbon-fiber-reinforced silicon carbide ceramic matrix composite. J Am Ceram Soc 2004;87(8):1536–42. [2] Zawada LP, Staehler J, Steel S. Consequence of intermittent exposure to moisture and salt fog on the high-temperature fatigue durability of several ceramic–matrix composites. J Am Ceram Soc 2003;86(8):1282–91. [3] Prewo KM, Batt JA. The oxidative stability of carbon fibre reinforced glass–matrix composites. J Mater Sci 1988;23:523–7. [4] Mah T, Hecht NL, McCullum DE, Hoenigman JR, Kim HM, Katz AP, et al. Thermal stability of sic fibres (Nicalon). J Mater Sci 1984;19:1191–201. [5] More KL, Tortorelli PF, Ferber MK, Keiser JR. Observations of accelerated silicon carbide recession by oxidation at high water-vapor pressures. J Am Ceram Soc 2000;83(1):211–3. [6] More KL, Tortorelli PF, Ferber MK, Walker LR, Keiser JR, Brentnall WD, Miralya N, Price JB. Exposure of ceramic and ceramic-matrix composites in simulated and actual combustor envi￾ronments. In: Proceedings of International Gas Turbine and Aero￾space Congress, 1999. Paper No. 99-GT-292. [7] Ferber MK, Lin HT, Keiser JR. Oxidation behavior of non-oxide ceramics in a high-pressure, high-temperature steam environment. In: Mechanical, thermal, and environmental testing and performance of ceramic composites and components. In: Jenkins MG, Lara-Curzio E, Gonczy ST, editors. ASTM STP, Vol. 1392. American Society for Testing and Materials; 2000. p. 210–5. [8] Haynes JA, Lance MJ, Cooley KM, Ferber MK, Lowden RA, Stinton DP. CVD mullite coatings in high-temperature, high-pressure air–H2O. J Am Ceram Soc 2000;83(3):657–9. [9] Opila EJ, Hann Jr RE. Paralinear oxidation of sic in water vapor. J Am Ceram Soc 1997;80(1):197–205. [10] Opila EJ. Oxidation kinetics of chemically vapor deposited silicon carbide in wet oxygen. J Am Ceram Soc 1994;77(3):730–6. [11] Opila EJ. Variation of the oxidation rate of silicon carbide with water vapor pressure. J Am Ceram Soc 1999;82(3):625–36. [12] Hermes EE, Kerans RJ. Degradation of non-oxide reinforcement and oxide matrix composites. Mat Res Soc, Symp Proc 1988;125:73–8. [13] Szweda A, Millard ML, Harrison MG. Fiber-reinforced ceramic– matrix composite member and method for making, US Pat. No. 5 601 674, 1997. [14] Sim SM, Kerans RJ. Slurry infiltration and 3-D woven composites. Ceram Eng Sci Proc 1992;13(9–10):632–41. [15] Moore EH, Mah T, Keller KA. 3D composite fabrication through matrix slurry pressure infiltration. Ceram Eng Sci Proc 1994;15(4):113–20. [16] Lewis MH, Cain MG, Doleman P, Razzell AG, Gent J. Development of interfaces in oxide and silicate matrix composites. In: Evans AG, Naslain RG, editors. High-temperature ceramic–matrix composites II: manufacturing and materials development. American Ceramic Society; 1995. p. 41–52. [17] Lange FF, Tu WC, Evans AG. Processing of damage-tolerant, oxidation-resistant ceramic matrix composites by a precursor infil￾tration and pyrolysis method. Mater Sci Eng A 1995;A195:145–50. [18] Lunderberg R, Eckerbom L. Design and processing of all-oxide composites. In: Evans AG, Naslain RG, editors. High-temperature ceramic–matrix composites ii: manufacturing and materials develop￾ment. American Ceramic Society; 1995. p. 95–104. [19] Mouchon E, Colomban P. Oxide ceramic matrix/oxide fiber woven fabric composites exhibiting dissipative fracture behavior. Compos￾ites 1995;26:175–82. [20] Morgan PED, Marshall DB. Ceramic composites of monazite and alumina. J Am Ceram Soc 1995;78(6):1553–63. [21] Tu WC, Lange FF, Evans AG. Concept for a damage-tolerant ceramic composite with strong interfaces. J Am Ceram Soc 1996;79(2):417–24. [22] Kerans RJ, Hay RS, Pagano NJ, Parthasarathy TA. The role of the fiber–matrix interface in ceramic composites. Am Ceram Soc Bull 1989;68(2):429–42. [23] Evans AG, Zok FW. Review: the physics and mechanics of fiber￾reinforced brittle matrix composites. J Mater Sci 1994;29:3857–96. [24] Kerans RJ, Parthasarathy TA. Crack deflection in ceramic compos￾ites and fiber coating design criteria. Composites: Part A 1999;30:521–4. 2098 M.B. Ruggles-Wrenn et al. / Composites Science and Technology 66 (2006) 2089–2099