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Titolo:
PROCESSING AND PROPERTIES OF ALN MATRIX COMPOSITE CERAMICS CONTAININGDISPERSED HARD MATERIALS
Autore:
BURKHARDT S; RIEDEL R; MULLER G;
Indirizzi:
TH DARMSTADT,FACHBEREICH MAT WISSENSCH,FACHGEBIET DISPERSE FESTSTOFFE,PETERSENSTR 23 D-64287 DARMSTADT GERMANY TH DARMSTADT,FACHBEREICH MAT WISSENSCH,FACHGEBIET DISPERSE FESTSTOFFED-64287 DARMSTADT GERMANY FRAUNHOFER INST SILICATFORSCH D-97082 WURZBURG GERMANY
Titolo Testata:
Journal of the European Ceramic Society
fascicolo: 1, volume: 17, anno: 1997,
pagine: 3 - 12
SICI:
0955-2219(1997)17:1<3:PAPOAM>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
FRACTURE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
S. Burkhardt et al., "PROCESSING AND PROPERTIES OF ALN MATRIX COMPOSITE CERAMICS CONTAININGDISPERSED HARD MATERIALS", Journal of the European Ceramic Society, 17(1), 1997, pp. 3-12

Abstract

The fabrication of AlN-(Y2O3) matrix ceramics reinforced with dispersed TiN or TiB2 particles is described and the resulting specimens are characterized by their mechanical properties and thermal conductivity. The microstructures of the TiN-reinforced specimens sintered at 1700 degrees C without isothermal hold show homogeneously distributed TiN particles (approximate to 1 mu m) in the fine-grained (1-2 mu m) AlN matrix. In contrast, the coarse TiB2 grains (2-3 mu m) of the specimens sintered at 1750 degrees C for 60 min are distributed inhomogeneously in the AlN matrix. Furthermore, the surface of the TiB2 grains reactedto TiN and BN during densification in 0.1 MPa N-2. The mechanical properties of the AlN-(0.5 wt% Y2O3)/5 wt% TiN composites sintered at 1700 degrees C without holding time were determined to be 12.5 GPa, 390 MPa and 3.6 MPa m(1/2) for the Vickers hardness HV, the four-point bending strength sigma(B) and the fracture toughness K-Ic, respectively. The AlN-(4 wt% Y2O3)/25 wt% TiN specimen sintered at 1900 degrees C for60 min gave 10.7 GPa for the Vickers hardness and 270 MPa for the four-point bending strength. The fracture toughness was determined to be 8.3 MPa m(1/2). In addition, the thermal conductivity of the AlN-TiN composites was of the order of 65 and 105 W m(-1) K-1 for composites sintered at 1700 degrees C without isothermal hold and at 1900 degrees Cfor 60 min, respectively. The AlN-(2 wt% Y2O3)10 wt% TiB2-containing specimen sintered at 1750 degrees C for 60 min has HV of 9.5 GPa, sigma(B) of 220 MPa and K-Ic of 3.7 MPa m(1/2).The influence of fracture mode and intrinsic stress on the mechanical properties is illustrated and discussed. Finally, the processing of AlN-(4 wt% Y2O3) ceramics without reinforcing particles coated with the TiN-particle reinforced AlNis reported. These layered materials exhibit a high thermal conductivity of 150 W m(-1) K-1 inside the body and enhanced hardness, fracturestrength and fracture toughness at the surface. (C) 1996 Elsevier Science Limited.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 19:23:44