Hot-Gas Spin Testing of Ceramic Radial Turbine Rotor at TIT 1400 C

Kobayashi, Yoshito; Matsuo, Eito; Inagaki, Toharu; Ozawa, Tadao

doi:10.4271/910401

Cited by 7 publications

(2 citation statements)

References 5 publications

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“…Considering that one of the must difficult components to form by conventional ceramic forming processing has been the radial turbine wheel, the development of the forming technique for a large, complex-shaped component as well as the development of a high strength and refractory material to achieve a turbine inlet temperature (TIT) of 1350 • C is required [1,25,39,[82][83][84]86]. Takatori et al [1] used for fabrication of radial turbine wheel Si 3 N 4 with additions of 5 wt% Y 2 O 3 and 5 wt% MgAl 2 O 4 (spinel) as additives.…”

Section: Injection Molding Of Si 3 N 4 Ceramicsmentioning

confidence: 99%

Dense and near-net-shape fabrication of Si3N4 ceramics

Bocanegra‐Bernal

Matović

2009

Materials Science and Engineering: A

120

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Section: Injection Molding Of Si 3 N 4 Ceramicsmentioning

confidence: 99%

Dense and near-net-shape fabrication of Si3N4 ceramics

Bocanegra‐Bernal

Matović

2009

Materials Science and Engineering: A

120

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“…The overall contribution to toughening of this effect has been modeled by either equation (31) or equation (32) [108].…”

Section: Ceramic Matrixmentioning

confidence: 99%

Mullite Whisker Enhanced Zirconia Toughened Alumina Ceramic Matrix Composite for High Temperature Applications

Robertson¹

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Ceramic Matrix Composites (CMC) are an attractive material for high temperature applications because they possess many of the high temperature capabilities of monolithic ceramics but also have enhanced mechanical properties due to their multi-phase structure. Recent successes with incorporating SiC fibre reinforced high temperature CMCs into advanced gas turbines have caused a renewed interest in applying CMCs to other high temperature applications. In this work, an oxide based CMC is proposed as a more oxidation resistant and cost effective CMC. Zirconia Toughened Alumina (ZTA), as the matrix, has enhanced toughness, strength, and creep resistance over single phase alumina or zirconia. ZTA can further be enhanced by the incorporation of single crystal mullite whiskers due to their stability in oxidizing atmospheres at high temperatures. Mullite whiskers are grown through the molten salt method and incorporated into the ZTA matrix using a colloidal processing route. The composition of the ZTA matrix is 15 wt% yttria stabilized zirconia (YSZ), 85 wt% α-alumina. The mullite whiskers make up 20 vol% of the composite, yielding a final composition of 71.6 wt% α-alumina, 12.7 wt% YSZ, and 15.6 wt% mullite. The green compacts are fired in a two stage sintering process incorporating atmospheric pressure sintering to 92% density (to seal the pore channels) and then hot isostatic pressure sintering to full density. The mechanical test results show that baseline ZTA (ZTA n ) with final porosity of 13.2% has a flexural strength of 61.71 ± 0.99 MPa at room temperature and 52.34 ± 15.72 MPa at 1200°C, a fracture toughness of 5.02 ± 0.21 MPa•m 1/2 and a hardness of 10.73 GPa. ZTA with whisker content (ZTA w ) with final porosity of 3.31% reached a flexural strength of 135.76 ± 1.30 MPa at room temperature, 80.52 ± 13.18 MPa at 1200 °C, a fracture toughness of 8.74 ± 0.24 MPa•m 1/2 and a hardness of 11.99 GPa. The addition of whiskers to ZTA has improved room temperature flexural strength by 120.0%, flexural strength at 1200°C by 53.8%, fracture toughness by 74.1%; but the whiskers have little effect on the hardness. Although high temperature flexural strength was improved by the addition of whiskers, the iv improvement to strength at high temperature was not as significant in ZTA w . Degradation of large whiskers was found during cyclic oxidation of ZTA w 1200 °C. v

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