Hostname: page-component-8448b6f56d-dnltx Total loading time: 0 Render date: 2024-04-19T20:11:45.266Z Has data issue: false hasContentIssue false

Ta and Nb Reinforced MoSi2

Published online by Cambridge University Press:  21 February 2011

David H. Carter
Affiliation:
Los Alamos National Laboratory, Mail Stop G770, Los Alamos, NM 87545
Patrick L. Martin
Affiliation:
Rockwell Science Center, 1049 Camino dos Rios, Thousand Oaks, CA 91360
Get access

Abstract

MoSi2 matrix composites have been recognized lately as potential materials for structural applications at elevated temperatures. Specifically, MoSi2 composites may exhibit useful properties at temperatures to 1400°C. Previous work improved the yield strength of MoSi2 at 1400°C by a factor of five through SiC whisker reinforcement. Current research is directed towards increasing the fracture toughness of MoSi2 through the addition of ductile phase reinforcements such as niobium and tantalum. The reaction between Nb and MoSi2 to form (Mo,Nb)5 Si3 proceeds with faster kinetics at hot isostatic press temperatures as low as 1100°C when compared to the reaction between Ta and MoSi2 to form (Mo,Ta)5Si3. This reaction product exhibits very poor properties, as evidenced by crack propagation through this layer during fracture. The feasibility of hot working these composites to produce tailored microstructures is examined.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Carter, David H., “SiC Whisker-Reinforced MoSi2,” Los Alamos National Laboratoryreport LA-11411-T, Master's Thesis, Massachusetts Institute of Technology (1988).Google Scholar
2. Long, R. A., “Fabrication and Properties of Hot-Pressed Molybdenum Disilicide,” report no. NACA RM E50F22 (1950).Google Scholar
3. Maxwell, W. A., “Properties of Certain Intermetallics as Related to Elevated-Temperature Applications. I - Molybdenum Disilicide,” report no. NACA RM E9G01 (1949).Google Scholar
4. Gibbs, W. S., Petrovic, J. J., and Honnell, R. E., “SiC Whisker-MoSi2 Matrix Composites,” Ceramic Engineering and Science Proceedings, 8 [7–8] 645648 (1987).Google Scholar
5. Carter, David H., Petrovic, John J., Honnell, Richard E., Gibbs, W. Scott, “SiC-MoSi2 Composites,” Los Alamos National Laboratory report LA-1 1577-MS (1989).Google Scholar
6. Peter Meschter, J., private communication.Google Scholar
7. Peter Meschter, J. and Daniel Schwartz, S., “Silicide-Matrix Materials for High-Temperature Applications,” Journal of Metals, 41 [11] 5255 (1989).Google Scholar
8. Fitzer, E. and Schmidt, F. K., “Silicon Diffusion in Me5 Si3 Phases of the Metals Niobium, Tantalum, Molybdenum, and Tungsten to 1700°C,” High Temperatures-High Pressures, 3 445460 (1971).Google Scholar
9. Fitzer, E. and Remmele, W., “Possibilities and Limits of Metal Reinforced Refractory Silicides, Especially Molybdenum Disilicide,” Fifth International Conference on Composite Materials (ICCM-5), 515 (1985).Google Scholar
10. Schlichting, J., “Molybdenum Disilicide as a Component of Modern High Temperature Composites,” High Temperatures-High Pressures, 10 [3] 241269 (1978).Google Scholar
11. Lipsitt, H. A., “Titanium Aluminides - An Overview,” High Temperature Ordered Intermetallic Alloys, ed. Koch, C. C., Liu, C. T., and Stoloff, N. S., MRS 39 351 (1985).Google Scholar