H.G. Holmquist et al./Composites: Part A 34(2003)163-170 observed to increase from -0.9 to -2.0 J/m- after two [4] Zawada LP. Longitudinal and transthickness tensile behavior of mpregnations of the matrix. Thus, literature and exper several oxide/oxide composites Ceram Engng Sci Proc 1998: 19(3): imental data are in close agreement with the value inferred Jurf RA Butner sC. Advances in oxid C ASME paper 99. from the analysis of the tube pressure tests. GT-190. New York: ASME: 1999 It can be concluded that the relatively low burst strength [6] Levi CG, Yang JY, Dalgleish BJ, Zok I AG. Processing and of the CFCC tubes in this study was not dictated by the rmance of an all-oxide ceramic J Am Ceram Soc fibres, but by the matrix; failure occurred by delamination 8:81(8:2077-86 The fabrication technique used in this work is well suited for [7] Goettler Rw, Keeley JT, Wagner RA. Ceramic composites technol tubular geometries, and the microstructure and consistency ogy development for industrial applications at Babcock and wilcox. Composites and functionally graded materials, vol. 80. ASME: 1997 achieved was notable 341-5. [8] McMahon TJ. Advanced hot gas filter development. Ceram Engng Sci 5. Summary [9] Davis JB, Marshall DB, Oka Ks, Housley RM, Morgan PED Ceramic or thermal protection systems. Composites, Part A 1999 30:483-8. The purpose of this work was to develop and demonstrate [10] National Materials Advisory Board, Committee on advanced fibers for the efficacy of a simple, low-cost method to fabricate all- posites. Publication oxide CFCC tubes. Fibre cloths were infiltrated with a pre Washington, DC: National Academy Press: 199 [11] Jones RH Henager Jr CH, Lewinsohn CA, Windisch consolidated slurry of mullite/alumina powders. By careful corrosion cracking of silicon carbide fibersilicon carbide control of the interparticle pair potential a high volume Am Ceram Soc2000:83(8):1999-2005 fraction of powders was achieved. The infiltrated fibre [12] Steyer TE, Zok FW. Stress rupture of an enhanced nicalon/silicon loths were rolled to tubular shapes. Efficient infiltration of carbide site at intermediate temperatures. J Am Ceram Soc the matrix into fibre tows and a homogeneous microstruc- 1998:81(8):2140- ture of the tubes were demonstrated the initial failure mode [13] Faber KT. Ceramic interfaces: properties and design. Annu Rey mater Sci 1997: 27: 499-524 of the tubes in pressure testing was delamination, which [14] Marshall DB. Davis JB. Morgan PED, Porter JR Interface materials took place at relatively low pressures and correspondingly for damage-tolerant oxide composites. Key Engng Mater 1997: 127- low hoop stresses(47+7 MPa). A simplified analysis in 131:27-36. terms of the required fracture energy at steady-state [15] Sudre O, Razzell AG, Molliex L, Holmquist M. Alumina single- propagation for a delamination crack was done. The inferred crystal fibre reinforced alumina matrix for combustor tiles. Ceram ngng sci proc998:194):273-80 value from the analysis and pressure testing, 1. 8 J/m", was [16) Holmquist M. LundbergR,SudreO,Razzell AG,MolliexL,BenoitJ in close agreement with data reported by others. It has beer Adlerborn J. Alumina/alumina composite with a porous zirconia shown that the described method can be used to fabricate interphase-processing, properties and component testing. J Eur tubular components, suitable in certain thermo-structural Ceram soc2000:20:599-606 [17] Lewis MH, Tye A, Butler E. Al-Dawery I. Development applications where requirements to sustain differential interfaces in oxide matrix composites. Key Engng Mater 1999: 164/ ressures across the wall are small, in a quick and 165:351-6 [18] 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. [19 Zawada LP. Longitudinal and transthickness tensile behavior of Acknowledgements several oxide/oxide composites. Ceram Engng Sci Proc 1998: 19(3) 27-39 This research was supported by the Army Research [201 Heathcote JA, Gong XY, Yang JY, Ramamurty U, Zok FW In-plane Office, DAAG55-98-1-0455 Magnus Holmquist thanks the mechanical properties of an all-oxide ceramic composite. J Am Ceram soc199982(10):2721-30 Hans Werthen Foundation for financial support. The authors [21] Levi CG, Zok FW, Yang JY, Mattoni M, Lofvander JPA would like to thank professor frank zok. dr james yan Microstructural design of stable porous matrices f and Mr hiroki Fujita for useful discussions nposites. Zeitschrift fuir Metallkunde 1999: 90(12): 1037-47 [22] Haslam JJ, Berroth KE, Lange FF. Processing and properties of an all- oxide composite with a porous matrix J Eur Ceram Soc 2000: 20 [23] Holmquist MG, Lange FF. Processing and properties of a porous oxide matrix composite reinforced with oxide fibers 1] Holmquist M, Lundberg R, Razzell T, Sudre O, Molliex L, Adlerborn Accepted for publication in J. Am. Ceram Soc. J. Development of ultra high temperature ceramic composites for gas [24] Lange FF. Levi CG, Zok Fw. Processing fiber reinforced ceramics urbine combustors. ASME paper 97-GT-413, New York: ASME: with porous matrices. In: Warren R, editor. Comprehensive composite materials. Amsterdam: Elsevier: 2000. chapter 14 2] Beesley CP. The application of CMCs in high integrity gas turbine [25] Lange FF. Colloidal processing of powder for reliable ceramics. Curr gines Key Engng Mater 1997: 127-131: 165-74 Opin Solid State Mater Sci 1998: 3: 496-500. [3] Razzell AG, Holmquist M, Molliex L, Sudre O Oxide/oxide ceramic [26] Manufacturers data. 3M Corporation, St Paul, MN, USA matrix composites in gas turbine combustors. ASME paper 98-GT-30, [27] Wilson DM. Statistical tensile strength of Nextel 610 and 720 fibres New York: ASME: 1998observed to increase from ,0.9 to ,2.0 J/m2 after two impregnations of the matrix. Thus, literature and exper￾imental data are in close agreement with the value inferred from the analysis of the tube pressure tests. It can be concluded that the relatively low burst strength of the CFCC tubes in this study was not dictated by the fibres, but by the matrix; failure occurred by delamination. The fabrication technique used in this work is well suited for tubular geometries, and the microstructure and consistency achieved was notable. 5. Summary The purpose of this work was to develop and demonstrate the efficacy of a simple, low-cost method to fabricate all￾oxide CFCC tubes. Fibre cloths were infiltrated with a pre￾consolidated slurry of mullite/alumina powders. By careful control of the interparticle pair potential a high volume fraction of powders was achieved. The infiltrated fibre cloths were rolled to tubular shapes. Efficient infiltration of the matrix into fibre tows and a homogeneous microstruc￾ture of the tubes were demonstrated. The initial failure mode of the tubes in pressure testing was delamination, which took place at relatively low pressures and correspondingly low hoop stresses (47 ^ 7 MPa). A simplified analysis in terms of the required fracture energy at steady-state propagation for a delamination crack was done. The inferred value from the analysis and pressure testing, 1.8 J/m2 , was in close agreement with data reported by others. It has been shown that the described method can be used to fabricate tubular components, suitable in certain thermo-structural applications where requirements to sustain differential pressures across the wall are small, in a quick and inexpensive way. Acknowledgements This research was supported by the Army Research Office, DAAG55-98-1-0455. Magnus Holmquist thanks the Hans Werthe´n Foundation for financial support. The authors would like to thank Professor Frank Zok, Dr James Yang and Mr Hiroki Fujita for useful discussions. References [1] Holmquist M, Lundberg R, Razzell T, Sudre O, Molliex L, Adlerborn J. Development of ultra high temperature ceramic composites for gas turbine combustors. ASME paper 97-GT-413, New York: ASME; 1997. [2] Beesley CP. The application of CMCs in high integrity gas turbine engines. Key Engng Mater 1997;127–131:165–74. [3] Razzell AG, Holmquist M, Molliex L, Sudre O. Oxide/oxide ceramic matrix composites in gas turbine combustors. ASME paper 98-GT-30, New York: ASME; 1998. [4] Zawada LP. Longitudinal and transthickness tensile behavior of several oxide/oxide composites. Ceram Engng Sci Proc 1998;19(3): 327–39. [5] Jurf RA, Butner SC. Advances in oxide/oxide CMC. ASME paper 99- GT-190, New York: ASME; 1999. [6] Levi CG, Yang JY, Dalgleish BJ, Zok FW, Evans AG. Processing and performance of an all-oxide ceramic composite. J Am Ceram Soc 1998;81(8):2077–86. [7] Goettler RW, Keeley JT, Wagner RA. Ceramic composites technol￾ogy development for industrial applications at Babcock and Wilcox. Composites and functionally graded materials, vol. 80. ASME; 1997. p. 341–5. [8] McMahon TJ. Advanced hot gas filter development. Ceram Engng Sci Proc 2000;21(3):47–57. [9] Davis JB, Marshall DB, Oka KS, Housley RM, Morgan PED. Ceramic composites for thermal protection systems. Composites, Part A 1999; 30:483–8. [10] National Materials Advisory Board, Committee on advanced fibers for high temperature ceramic composites. Publication NMAB-494, Washington, DC: National Academy Press; 1998. [11] Jones RH, Henager Jr CH, Lewinsohn CA, Windisch CF. Stress￾corrosion cracking of silicon carbide fiber/silicon carbide composite. J Am Ceram Soc 2000;83(8):1999–2005. [12] Steyer TE, Zok FW. Stress rupture of an enhanced nicalon/silicon carbide composite at intermediate temperatures. J Am Ceram Soc 1998;81(8):2140–6. [13] Faber KT. Ceramic composite interfaces: properties and design. Annu Rev Mater Sci 1997;27:499–524. [14] Marshall DB, Davis JB, Morgan PED, Porter JR. Interface materials for damage-tolerant oxide composites. Key Engng Mater 1997;127– 131:27–36. [15] Sudre O, Razzell AG, Molliex L, Holmquist M. Alumina single￾crystal fibre reinforced alumina matrix for combustor tiles. Ceram Engng Sci Proc 1998;19(4):273–80. [16] Holmquist M, Lundberg R, Sudre O, Razzell AG, Molliex L, Benoit J, Adlerborn J. Alumina/alumina composite with a porous zirconia interphase—processing, properties and component testing. J Eur Ceram Soc 2000;20:599–606. [17] Lewis MH, Tye A, Butler E, Al-Dawery I. Development of interfaces in oxide matrix composites. Key Engng Mater 1999;164/ 165:351–6. [18] 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. [19] Zawada LP. Longitudinal and transthickness tensile behavior of several oxide/oxide composites. Ceram Engng Sci Proc 1998;19(3): 327–39. [20] Heathcote JA, Gong XY, Yang JY, Ramamurty U, Zok FW. In-plane mechanical properties of an all-oxide ceramic composite. J Am Ceram Soc 1999;82(10):2721–30. [21] Levi CG, Zok FW, Yang JY, Mattoni M, Lo¨fvander JPA. Microstructural design of stable porous matrices for all-oxide ceramic composites. Zeitschrift fu¨r Metallkunde 1999;90(12):1037–47. [22] Haslam JJ, Berroth KE, Lange FF. Processing and properties of an all￾oxide composite with a porous matrix. J Eur Ceram Soc 2000;20: 607–18. [23] Holmquist MG, Lange FF. Processing and properties of a porous oxide matrix composite reinforced with continuous oxide fibers. Accepted for publication in J. Am. Ceram. Soc. [24] Lange FF, Levi CG, Zok FW. Processing fiber reinforced ceramics with porous matrices. In: Warren R, editor. Comprehensive composite materials. Amsterdam: Elsevier; 2000. chapter 14. [25] Lange FF. Colloidal processing of powder for reliable ceramics. Curr Opin Solid State Mater Sci 1998;3:496–500. [26] Manufacturers data. 3M Corporation, St Paul, MN, USA. [27] Wilson DM. Statistical tensile strength of Nextel 610 and 720 fibres. J Mater Sci 1997;32:2535–42. M.G. Holmquist et al. / Composites: Part A 34 (2003) 163–170 169