Chapter 85. Toughness and Hardness of Lps-Sic and Lps-Sic Based Composites
- Edgar Lara-Curzio and
- Michael J. Readey
Published Online: 26 MAR 2008
Copyright © 2004 The American Ceramic Society
28th International Conference on Advanced Ceramics and Composites A: Ceramic Engineering and Science Proceedings, Volume 25, Issue 3
How to Cite
Schwetz, K. A., Kempf, T., Saldsiedcr, D. and Telle, R. (2004) Toughness and Hardness of Lps-Sic and Lps-Sic Based Composites, in 28th International Conference on Advanced Ceramics and Composites A: Ceramic Engineering and Science Proceedings, Volume 25, Issue 3 (eds E. Lara-Curzio and M. J. Readey), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291184.ch85
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 2004
Print ISBN: 9780470051498
Online ISBN: 9780470291184
Liquid-phase-sintered silicon carbide with minimized residual porosity and very fine grain size (≤1 μm) is attractive as a high performance armor material due to its high hardness, high toughness and its potential for lower cost, especially when fabricated by gas pressure sintering. This study provides hardness (Vickers, HV-10) and fracture toughness (SEPB) data of YAG/AlN-doped LPS-SiC as a function of (i) the volume fraction of the YAG-based binder phase, (ii) the content of free carbon, (iii) the toughening by in-situ formed SiC platelets and (iv) the toughening by dispersion of SiC, TiB2 and Si3N4 particles.
The results indicate that higher amounts of the YAG based binder phase as well as additions of ceramic particles (>10 wt-%) reduce the hardness of LPS-SiC, whereas toughness may vary from 3.3 to 6.2 MPa' m1/2. Toughness is controlled by (i) free carbon (chemical composition of the grain boundary), (ii) microstructure (grain size/shape of grains/interface strength), and (iii) amount of dispersed ceramic particles. Hardness is controlled primarily by the microstructural grain size and the grain boundary chemistry.