Chapter 6. Mechanical Properties of Hot Pressed SiC Platelet-Reinforced MoSi2

  1. John B. Wachtman Jr
  1. Kerry K. Richardson and
  2. Douglas W. Freitag

Published Online: 26 MAR 2008

DOI: 10.1002/9780470313848.ch6

Proceedings of the 15th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 12, Issue 9/10

Proceedings of the 15th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 12, Issue 9/10

How to Cite

Richardson, K. K. and Freitag, D. W. (1991) Mechanical Properties of Hot Pressed SiC Platelet-Reinforced MoSi2, in Proceedings of the 15th Annual Conference on Composites and Advanced Ceramic Materials, Part 2 of 2: Ceramic Engineering and Science Proceedings, Volume 12, Issue 9/10 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470313848.ch6

Author Information

  1. LTV Missiles and Electronics Group Missiles Division P.O. Box 650003 Dallas, TX 75265

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1991

ISBN Information

Print ISBN: 9780470375105

Online ISBN: 9780470313848

SEARCH

Keywords:

  • monolithic;
  • temperature;
  • molybdenum;
  • platelets;
  • hexagonal

Summary

Mechanical characteristics of two different purity molybdenum disilicide (MoSi2) intermetalllic matrices reinforced with 20 vol% silicon carbide platelets were studied. Matrices examined had purities of 99.5% and 99.95%. Mechanical properties tested included flexure strength, fracture toughness, and pin shear strength. Mechanical property data were collected between room temperature and 1650°C. At room temperature, flexure strengths were increased by 45% and 98% for the low-purity and high-purity MoSi2 composites, respectively, when compared to monolithic MoSi2 Elevated temperature strengths were increased by 142% at 1093°C for the low-purity MoSi2 composite and 150% at 815°C for the high-purity MoSi2 composite when compared to monolithic MoSi2. At temperatures greater than 815°C the low-purity MoSi2 specimens had higher average flexure strengths than the high-purity specimens. Below the brittle-to-ductile transition temperature, ∼1000°C, both compositions exhibit comparable modes of failure. Above the brittle-to-ductile transition temperature, the modes of failure vary with composition. High-purity composites failed intergranularly while low-purity composites failed transgranularfy. Fracture toughness was dramatically increased when compared to monolithic MoSi2. Improved fracture toughness was maintained to 815°C and then decreased slightly beyond temperatures of 1093°C. Minimum pin shear strength at room temperature was 54.4 MPa and was maintained to 1093°C before decreasing at higher temperatures. Ultimate pin shear strength values were not measured due to premature failure of the test specimens in three-point bending.