Evaluation of Reinforced Plastics for High Temperature Structural Applications

2009 ◽  
pp. 12-12-16
Author(s):  
V. F. Hribar ◽  
A. M. Dowell
Keyword(s):  
High Temperature ◽  
Reinforced Plastics ◽  
Structural Applications

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

Crystallization sequence of an A1N-Y2O3-SiO2 glass-ceramic

1986 ◽  
Vol 44 ◽  
pp. 446-447
Author(s):  
T.R. Dinger ◽  
G. Thomas
Keyword(s):  
High Temperature ◽  
Glass Ceramic ◽  
Crystallization Behavior ◽  
High Stress ◽  
Crystallization Sequence ◽  
Sio2 Glass ◽  
Structural Applications ◽  
Ceramic Precursors

The use of Si3N4, alloys for high temperature, high stress structural applications has prompted numerous studies of the oxynitride glasses which exist as intergranular phases in their microstructures. Oxynitride glasses have been investigated recently in their bulk form in order to understand their crystallization behavior for subsequent Si3N4 applications and to investigate their worth as glass-ceramic precursors. This research investigates the crystallization sequence of a glass having a normalized composition of Y26Si30Al11 ON11 and lying in the A1N-Y2O3-SiO2 section of the Y-Si-Al-O-N system. Such glasses exist as intergranular phases in the technologically important Y2O3/Al2O3-fluxed Si3N4 alloys.

Electron energy loss near edge structures of intermetallic alloys and grain boundaries in NiAl

1996 ◽  
Vol 54 ◽  
pp. 522-523
Author(s):  
G.A. Botton ◽  
C.J. Humphreys
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Energy Loss ◽  
Grain Boundaries ◽  
Industrial Applications ◽  
Edge Structure ◽  
Structural Applications ◽  
Yield Behaviour ◽  
Late Transition ◽  
Metal Aluminides

Transition metal aluminides are of great potential interest for high temperature structural applications. Although these materials exhibit good mechanical properties at high temperature, their use in industrial applications is often limited by their intrinsic room temperature brittleness. Whilst this particular yield behaviour is directly related to the defect structure, the properties of the defects (in particular the mobility of dislocations and the slip system on which these dislocations move) are ultimately determined by the electronic structure and bonding in these materials. The lack of ductility has been attributed, at least in part, to the mixed bonding character (metallic and covalent) as inferred from ab-initio calculations. In this work, we analyse energy loss spectra and discuss the features of the near edge structure in terms of the relevant electronic states in order to compare the predictions on bonding directly with spectroscopic experiments. In this process, we compare spectra of late transition metal (TM) to early TM aluminides (FeAl and TiAl) to assess whether differences in bonding can also be detected. This information is then discussed in terms of bonding changes at grain boundaries in NiAl.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

WC-3015 Alloy

Alloy Digest ◽  
1974 ◽  
Vol 23 (5) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Base Alloy ◽  
Heat Treating ◽  
Rolled Sheet ◽  
Good Oxidation Resistance ◽  
Structural Applications ◽  
Cold Rolled

Abstract WC-3015 is a columbium-base alloy developed for structural applications in high-temperature oxidizing environments. It is characterized by good oxidation resistance, good mechanical properties and compatibility with silicide coatings. Cold-rolled sheet can be joined and welded without cracking. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-21. Producer or source: Wah Chang, a Teledyne Corporation.

High-temperature carbon plastics based on thermoreactive polyimide binder

2020 ◽  
pp. 89-102
Author(s):  
M. I. Valueva ◽  
I. V. Zelenina ◽  
M. A. Zharinov ◽  
M. A. Khaskov
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Strength Properties ◽  
High Glass Transition Temperature ◽  
Reinforced Plastics ◽  
Carbon Plastics ◽  
Fundamental Possibility ◽  
Fiber Reinforced Plastics

The article presents results of studies of experimental carbon plastics based on thermosetting PMRpolyimide binder. Сarbon fiber reinforced plastics (CFRPs) are made from prepregs prepared by melt and mortar technologies, so the rheological properties of the polyimide binder were investigated. The heat resistance of carbon plastics was researched and its elastic-strength characteristics were determined at temperatures up to 320°С. The fundamental possibility of manufacturing carbon fiber from prepregs based on polyimide binder, obtained both by melt and mortar technologies, is shown. CFRPs made from two types of prepregs have a high glass transition temperature: 364°C (melt) and 367°C (solution), with this temperature remaining at the 97% level after boiling, and also at approximately the same (86–97%) level of conservation of elastic strength properties at temperature 300°С.

Recent Advances in Development and Processing of Titanium Aluminide Alloys

2000 ◽  
Vol 646 ◽  
Author(s):  
Fritz Appel ◽  
Helmut Clemens ◽  
Michael Oehring
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Environmental Stability ◽  
Physical Metallurgy ◽  
Specific Strength ◽  
Wide Range ◽  
Structural Applications ◽  
Strength And Stiffness ◽  
Nickel Base

ABSTRACTIntermetallic titanium aluminides are one of the few classes of emerging materials that have the potential to be used in demanding high-temperature structural applications whenever specific strength and stiffness are of major concern. However, in order to effectively replace the heavier nickel-base superalloys currently in use, titanium aluminides must combine a wide range of mechanical property capabilities. Advanced alloy designs are tailored for strength, toughness, creep resistance, and environmental stability. Some of these concerns are addressed in the present paper through specific comments on the physical metallurgy and technology of gamma TiAl-base alloys. Particular emphasis is placed on recent developments of TiAl alloys with enhanced high-temperature capability.

scholarly journals Development of Creep-Resistant, Alumina-Forming Ferrous Alloys for High-Temperature Structural Use

2018 ◽  
Author(s):  
Y. Yamamoto ◽  
M. P. Brady ◽  
G. Muralidharan ◽  
B. A. Pint ◽  
P. J. Maziasz ◽  
...  
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Extreme Environments ◽  
Alloy Design ◽  
Austenitic Steels ◽  
Strength Development ◽  
Second Phase ◽  
Ferrous Alloys ◽  
Steel Alloys ◽  
Structural Applications

This paper overviews recent advances in developing novel alloy design concepts of creep-resistant, alumina-forming Fe-base alloys, including both ferritic and austenitic steels, for high-temperature structural applications in fossil-fired power generation systems. Protective, external alumina-scales offer improved oxidation resistance compared to chromia-scales in steam-containing environments at elevated temperatures. Alloy design utilizes computational thermodynamic tools with compositional guidelines based on experimental results accumulated in the last decade, along with design and control of the second-phase precipitates to maximize high-temperature strengths. The alloys developed to date, including ferritic (Fe-Cr-Al-Nb-W base) and austenitic (Fe-Cr-Ni-Al-Nb base) alloys, successfully incorporated the balanced properties of steam/water vapor-oxidation and/or ash-corrosion resistance and improved creep strength. Development of cast alumina-forming austenitic (AFA) stainless steel alloys is also in progress with successful improvement of higher temperature capability targeting up to ∼1100°C. Current alloy design approach and developmental efforts with guidance of computational tools were found to be beneficial for further development of the new heat resistant steel alloys for various extreme environments.

Superhard TiB2 - Based Composites with Different Matrix Fabricated from Elemental Powders by SHS-p-HIP

2012 ◽  
Vol 77 ◽  
pp. 146-152 ◽  
Author(s):  
Marta Ziemnicka-Sylwester
Keyword(s):  
High Temperature ◽  
Hot Isostatic Pressing ◽  
Cutting Tools ◽  
Consolidation Process ◽  
Pressing Method ◽  
High Temperature Synthesis ◽  
Structural Applications ◽  
Improve Fracture Toughness ◽  
Ball Milling Technique ◽  
Main Component

TiB2is a superhard, high-temperature and high corrosion resistant material and it is under consideration for tungsten-free cutting tools and high temperature structural applications. Although such a covalent compound requires significantly elevated temperature for the consolidation, great exothermicity of TiB2synthesis by means of SHS (Self-propagating High-temperature Synthesis) can be “ïn situ” utilized. In this study, TiB2-based composites are fabricated from titanium, boron and binder metal. In order to optimize consolidation process and improve fracture toughness of the products, three types of binder, based on cobalt, nickel or copper were investigated. In respect to hardness, limited amount of binder, 5, 10 or 15 vol.% respectively, were applied; each time 5 vol.% of Ti addition for reaction with boron completeness was used. The TiB2based composites were fabricated from elements in one process by means of the SHS process combined with p-HIP (pseudo-hot isostatic pressing) method. The raw elemental powders were homogenized by wet mixing using ball milling technique. Dried mixtures were pressed into a compact, coiled by heating element and then exposed to the SHS-p-HIP process. After SHS initiation, the compact was pressed pseudo-isostatically under pressure of 190MPa for 5 min. The sintering additives and their concentrations significantly affected the consolidation process as well as the properties of composites. The highest hardness was obtained for samples sintered with cobalt, containing intermetallic binder. However, elemental metal binder was detected as a main component for samples sintered with copper. The relative density, SEM microstructure, phase composition and hardness are compared in this study.

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