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Investigation of the physical and mechanical properties of hot-pressed machinable Si3N4/h-BN composites and FGM
- Source :
-
Materials Science & Engineering: B . Mar2002, Vol. 90 Issue 3, p261. 8p. - Publication Year :
- 2002
-
Abstract
- A new design method of machinable ceramic composites was proposed, which applies the graded-structure concept to the design of machinable Si3N4 ceramics. Silicon nitride/hexagonal boron nitride (h-BN) ceramic composites and functionally graded materials were fabricated by hot pressing at 1750 °C for 2 h, varying the alignment of the amount of hexagonal BN using powder layering method. The improved machinability of Si3N4/h-BN composite can be attributed to addition of layered structure hexagonal BN. Hexagonal BN possesses excellent cleavage planes perpendicular to the c-axis. Ease of machining depends on degree of crystal interlocking; hence volume content of h-BN crystals and their aspect ratio affect machinability. The texture of h-BN and β-Si3N4 was observed during hot pressing sintering. Physical and mechanical properties of Si3N4/h-BN with different content of h-BN were investigated, such as bulk density, Vickers''s hardness, flexural strength, and elastic modulus. All of these properties are important for the design of the machinable Si3N4/h-BN FGM (Functionally Graded Materials). [Copyright &y& Elsevier]
- Subjects :
- *CERAMICS
*MACHINABILITY of metals
Subjects
Details
- Language :
- English
- ISSN :
- 09215107
- Volume :
- 90
- Issue :
- 3
- Database :
- Academic Search Index
- Journal :
- Materials Science & Engineering: B
- Publication Type :
- Academic Journal
- Accession number :
- 7762195
- Full Text :
- https://doi.org/10.1016/S0921-5107(01)01048-0