Electrodeposited Cobalt-Tungsten as a High-Temperature Diffusion Barrier for Graphite-Fiber/Nickel Composites

1993 ◽  
Vol 318 ◽  
Author(s):  
N. S. Wheeler ◽  
D. S. Lashmore
Keyword(s):  
High Temperature ◽  
Diffusion Barrier ◽  
Alloy Coating ◽  
Matrix Composites ◽  
Graphite Fiber ◽  
Nickel Metal ◽  
Aerospace Applications ◽  
Temperature Diffusion ◽  
Graphite Fibers ◽  
Nickel Composites

ABSTRACTThere is a growing demand for advanced composites which can maintain their structural strength in high-temperature environments, particularly for aerospace applications. The use of graphite fiber/nickel metal matrix composites would be desirable if the deterioration of mechanical properties resulting from interdiffusion of carbon and nickel at temperatures in excess of 600°C could be avoided. The present research concerns an electrodeposited cobalt alloy coating containing 5-10.5 at-% tungsten, which was designed to serve as a diffusion barrier between graphite fibers and a nickel matrix. The resulting graphite/Co-W/Ni composite was tested under various time/temperature conditions, and the coating was shown to inhibit diffusion for up to 24 hr at 800°C. Annealed and unannealed coated fibers were analyzed by x-ray diffraction and by transmission electron microscopy The as-deposited coating was found to contain both h.c.p. and f.c.c. cobalt, whereas only f.c.c. was observed after annealing at 1100°C for 1.5 hours. WC was found at the coating/fiber interface.

Damage Mechanisms in Polymer Matrix Composites in Extreme Environments

2006 ◽  
Vol 324-325 ◽  
pp. 663-666 ◽  
Author(s):  
Maciej S. Kumosa
Keyword(s):  
High Temperature ◽  
Polymer Matrix ◽  
High Voltage ◽  
Polymer Matrix Composites ◽  
Rocket Engine ◽  
Extreme Environments ◽  
Combined Cycle ◽  
Matrix Composites ◽  
Aerospace Applications ◽  
Liquid Propellant Rocket Engine

In this work, potential problems with the application of polymer matrix composites (PMC) in extreme environments [1] is discussed. Then, two specific examples of the applications of PMCs in high voltage [2-7] and high temperature [8-15] situations are evaluated. The first example deals with damage evolution in high voltage composite insulators [2-7] with PMC rods subjected to a combined action of extreme mechanical, electrical and environmental stresses. These insulators are widely used in transmission line and substation applications around the world. Subsequently, advanced high temperature graphite/polyimide composites [8-15] are evaluated for aerospace applications. The composite investigated in this project were used to manufacture and successfully test a Rocket Based Combined Cycle (RBCC) third-generation, reusable liquid propellant rocket engine, which is one possible engine for a future single-stage-to-orbit vehicle [8].

scholarly journals Dispersion analysis of carbon nanotubes, carbon onions, and nanodiamonds for their application as reinforcement phase in nickel metal matrix composites

RSC Advances ◽  
2015 ◽  
Vol 5 (115) ◽  
pp. 95149-95159 ◽  
Author(s):  
L. Reinert ◽  
M. Zeiger ◽  
S. Suárez ◽  
V. Presser ◽  
F. Mücklich
Keyword(s):  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Carbon Nanoparticles ◽  
Dispersion Analysis ◽  
Matrix Composites ◽  
Nickel Metal ◽  
Aspect Ratios ◽  
Nickel Composites

Low aspect ratios and sp3 hybridization of carbon nanoparticles benefit both, small agglomerate sizes in ethylene glycol and nickel composites.

An Overview of Potential Titanium Aluminide Composites in Aerospace Applications

1992 ◽  
Vol 273 ◽  
Author(s):  
James M. Larsen ◽  
William C. Revelos ◽  
Mary L. Gambone
Keyword(s):  
High Temperature ◽  
Air Force ◽  
Titanium Aluminide ◽  
High Performance ◽  
Matrix Composites ◽  
Enabling Technology ◽  
Aerospace Vehicles ◽  
Aerospace Applications ◽  
Monotonic Properties ◽  
Temperature Time

ABSTRACTHigh-temperature, light-weight materials represent enabling technology in the continued evolution of high-performance aerospace vehicles and propulsion systems being pursued by the U.S. Air Force. In this regard, titanium aluminide matrix composites appear to offer unique advantages in terms of a variety of weightspecific properties at high temperatures. However, a key requirement for eventual structural use of these materials is a balance of mechanical properties that can be suitably exploited by aircraft and engine designers without compromising reliability. An overview of the current capability of titanium aluminide composites is presented, with an effort to assess the balance of properties offered by this class of materials. Emphasis is given to life-limiting cyclic and monotonic properties and the roles of high-temperature, time-dependent deformation and environmental effects. An attempt is made to assess the limitations of currently available titanium aluminide composites with respect to application needs and to suggest avenues for improvements in key properties.

TEM study of boron additions to cobalt aluminide

1988 ◽  
Vol 46 ◽  
pp. 546-547
Author(s):  
Gerald B. Feldewerth
Keyword(s):  
High Temperature ◽  
Turbine Engines ◽  
Major Drawback ◽  
University Of Missouri ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Wide Range ◽  
Ordered Alloys ◽  
The University ◽  
Very High

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.

Deformation at interfaces of Ti-6Al-4V/SiC fiber composites

1992 ◽  
Vol 50 (1) ◽  
pp. 158-159
Author(s):  
Warren J. Moberly ◽  
Daniel B. Miracle ◽  
S. Krishnamurthy
Keyword(s):  
Thermal Stresses ◽  
Load Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Hot Isostatic Pressing ◽  
Matrix Composites ◽  
Ongoing Research ◽  
Aerospace Applications ◽  
Sic Fiber ◽  
The Matrix ◽  
Intermetallic Matrix Composites

Titanium-aluminum alloy metal matrix composites (MMC) and Ti-Al intermetallic matrix composites (IMC), reinforced with continuous SCS6 SiC fibers are leading candidates for high temperature aerospace applications such as the National Aerospace Plane (NASP). The nature of deformation at fiber / matrix interfaces is characterized in this ongoing research. One major concern is the mismatch in coefficient of thermal expansion (CTE) between the Ti-based matrix and the SiC fiber. This can lead to thermal stresses upon cooling down from the temperature incurred during hot isostatic pressing (HIP), which are sufficient to cause yielding in the matrix, and/or lead to fatigue from the thermal cycling that will be incurred during application, A second concern is the load transfer, from fiber to matrix, that is required if/when fiber fracture occurs. In both cases the stresses in the matrix are most severe at the interlace.

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