scholarly journals Recent Advances and Developments in Refractory Alloys

1993 ◽  
Vol 322 ◽  
Author(s):  
T.G. Nieh ◽  
J. Wadsworth
Keyword(s):  
High Temperature ◽  
Refractory Metal ◽  
Metal Alloys ◽  
High Temperature Strength ◽  
Refractory Alloys ◽  
Aerospace Applications ◽  
Wide Range ◽  
Recent Developments ◽  
Refractory Metal Alloys

AbstractRefractory metal alloys based on Mo, W, Re, Ta, and Nb (Cb) find applications in a wide range of aerospace applications because of their high melting points and high-temperature strength. In this paper, we present recent progress in the understanding and applications of these alloys. Recent studies to improve the oxidation and mechanical behavior of refractory metal alloys, and particularly Nb alloys, will also be discussed. Some Re structures, for extremely high temperature applications (> 2000°C), made by CVD and P/M processes, are also illustrated. Interesting work on the development of new W alloys (W-HfC-X) and the characterization of some commercial refractory metals, e.g., K-doped W, TZM, and Nb-l%Zr, continues. Finally, recent developments in high temperature composites reinforced with refractory metal filaments, and refractory metal-based intermetallics, e.g., Nb3A1, Nb2Be17, and MoSi2, are briefly described.

scholarly journals High Temperature Sulfidation and Oxidation Behavior of Sputter-Deposited Al-refractory Metal Alloys

1996 ◽  
Vol 37 (3) ◽  
pp. 379-382 ◽  
Author(s):  
H. Mitsui ◽  
H. Habazaki ◽  
E. Akiyama ◽  
A. Kawashima ◽  
K. Asami ◽  
...  
Keyword(s):  
High Temperature ◽  
Refractory Metal ◽  
Oxidation Behavior ◽  
Metal Alloys ◽  
Sputter Deposited ◽  
Refractory Metal Alloys

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

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.

scholarly journals Use of Ultrasonic Sensors for Characterization of Membrane Fouling and Cleaning

2008 ◽  
Vol 3 (2) ◽  
pp. 155892500800300 ◽  
Author(s):  
Elmira Kujundzic ◽  
Keith Cobry ◽  
Alan R. Greenberg ◽  
Mark Hernandez
Keyword(s):  
Time Domain ◽  
Membrane Fouling ◽  
Permeation Rate ◽  
Acoustic Microscopy ◽  
Membrane Separations ◽  
Direct Observations ◽  
Wide Range ◽  
Recent Developments ◽  
Acoustic Techniques

The modern challenges for membrane separations in a wide range of processes require more sophisticated approaches for the detection and remediation of fouling, i.e., the association of solutes, particulate matter, and colloids on and/or within a membrane. Most commonly, fouling is assessed from inferred measurements of permeation rate and/or permeate quality. The use of acoustic techniques for direct observations of membrane fouling was introduced over 10 years ago. We summarize here, recent developments in ultrasonic reflectometry that use both time-domain and frequency-domain spectra for noninvasive, real-time assessments of fouling in a variety of module configurations and geometries. In addition, we describe recent developments and applications of scanning acoustic microscopy (SAM) for post-mortem characterization of membranes with particular emphasis on biofouling.

scholarly journals Coating Reactions on Vanadium and V-Si-B Alloys during Powder Pack-Cementation

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4099
Author(s):  
Georg Hasemann ◽  
Chad Harris ◽  
Manja Krüger ◽  
John H. Perepezko
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Refractory Metal ◽  
Pack Cementation ◽  
Solid Solution Phase ◽  
Major Drawback ◽  
Three Phase ◽  
Structural Applications ◽  
New Type ◽  
Refractory Metal Alloys

Alloys in the V-Si-B system are a new and promising class of light-weight refractory metal materials for high temperature applications. Presently, the main attention is focused on three-phase alloy compositions that consist of a vanadium solid solution phase and the two intermetallic phases V3Si and V5SiB2. Similar to other refractory metal alloys, a major drawback is the poor oxidation resistance. In this study, initial pack-cementation experiments were performed on commercially available pure vanadium and a three-phase alloy V-9Si-5B to achieve an oxidation protection for this new type of high temperature material. This advance in oxidation resistance now enables the attractive mechanical properties of V-Si-B alloys to be used for high temperature structural applications.

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