High-Temperature Mechanical Behavior and Phase Morphology of Poly(Tetrafluoroethylene)/Siloxane Nanocomposites Used as Ultra Low-k Dielectrics

2000 ◽  
Vol 612 ◽  
Author(s):  
Ping Xu ◽  
Shichun Qu ◽  
Tom Rosenmayer ◽  
Min Y. Lin

AbstractPoly(tetrafluoroethylene) (PTFE)/siloxane nanocomposites have been prepared as ultra low-k dielectrics. These new nanocomposites show excellent high-temperature mechanical properties compared to unfilled PTFE while their dielectric constant almost remains unchanged. Specifically, the data from the dynamic mechanical study indicates that these nanocomposites have the mechanical behavior similar to that of crosslinked polymers. Small-angle neutron scattering (SANS) has been carried out to characterize the phase morphology of the PTFE/siloxane nanocomposites and the size of the inorganic networks. It has been shown that no phase separations or orientations appear in these nanocomposites in the range of 12 to 469 nm. These SANS results suggest that these materials are single-phase nanocomposites that are very homogeneous and isotropic. They are basically PTFE-based molecular composites.

1986 ◽  
Vol 81 ◽  
Author(s):  
S. E. Hsu ◽  
N. N. Hsu ◽  
C. H. Tong ◽  
C. Y. Ma ◽  
S. Y. Lee

AbstractHigh temperature mechanical properties of various Zr and Cr strengthened single phase Ni3Al are investigated, with emphasis on the ability of each element to elevate Tp, the temperature corresponding to the peak yield strength. It is observed that Zr is a very effective strengthener, more so below Tp than above it, while a combination of Cr and Zr is capable of shifting Tp to a higher temperature. The combination results in an effective improvement of the rupture strength of Ni3Al. The strengthening mechanisms of each element will be discussed in this paper.


Author(s):  
B. J. Hockey

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.


Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.


Author(s):  
W. M. Sherman ◽  
K. M. Vedula

The strength to weight ratio and oxidation resistance of NiAl make this ordered intermetallic, with some modifications, an attractive candidate to compete with many superalloys for high temperature applications. Recent studies have shown that the inherent brittleness of many polycrystalline intermetallics can be overcome by micro and macroalloying. It has also been found that the high temperature mechanical properties of NiAl can be enhanced through the addition of Nb by powder metallurgical techniques forming a dispersed second phase through interdiffusion in a polycrystalline matrix. A drop in the flow stress is observed however in a NiAl-2 at.% Nb alloy after 0.2 % strain during constant strain rate hot compression testing at 1025°C. The object of this investigation was to identify the second phase and to determine the cause of the flow stress drop.


Alloy Digest ◽  
1975 ◽  
Vol 24 (9) ◽  

Abstract BERYLCO NICKEL ALLOY 440 is an age-hardenable nickel-beryllium-titanium alloy that offers high strength, excellent spring properties outstanding formability, good high-temperature mechanical properties, and resistance to corrosion and fatigue. Complex shapes can be produced in the solution-treated (soft) condition and then aged to a minimum tensile strength of 215,500 psi. It is used for mechanical and electrical/electronic components in the temperature range -320 to 800 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-94. Producer or source: Kawecki Berylco Industries Inc.. Originally published September 1964, revised September 1975.


Alloy Digest ◽  
1972 ◽  
Vol 21 (3) ◽  

Abstract COPPER ALLOY No. 230 is a single-phase brass containing 15% zinc which is the most widely used of the low zinc brasses. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness and creep. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-252. Producer or source: Brass mills.


Alloy Digest ◽  
1973 ◽  
Vol 22 (1) ◽  

Abstract HASTELLOY alloy S is a nickel-base high-temperature alloy having excellent thermal stability, good high-temperature mechanical properties and excellent resistance to oxidation up to 2000 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-184. Producer or source: Stellite Division, Cabot Corporation.


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