Title

Pressureless Sintering of B₄C Whisker Reinforced Al₂O₃ Matrix Composites

Abstract

Al2O3-B4C whisker composites have been successfully densified by pressureless sintering. Low oxygen partial pressures, below 10 atmospheres, were determined to be suitable for the composite densification, and the maximum densities were achieved at 1800?�C for 60 minutes. The B4C whiskers were screened classified into five size fractions and the effect of size and size distribution on the densification were studied. The small whiskers with a narrow size distribution (?325?+?400 mesh) yielded the highest density results. The maximum value of relative densities was 98%, 97%, 94% and 89% at 10, 20, 30 and 40 vol ?% B4C whiskers, respectively. Addition of B4C between 5 and 15 vol?% proved to be a sintering aid to the alumina densification via mechanisms other than being a grain growth inhibitor. An increased fracture toughness up to 6.2 MPa�m TeX was achieved in the composites containing 10�20 vol?% B4C whiskers.

Department(s)

Materials Science and Engineering

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2000 Springer Verlag, All rights reserved.


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