Radiation Effects On The Low Temperature Coefficient Of Thermal Expansion Of Low-CTE Materials

1989 ◽  
Author(s):  
Paige L. Higby ◽  
Charles G. Askins ◽  
Jackie A. Ruller ◽  
E.Joseph Friebele
Keyword(s):  
Thermal Expansion ◽  
Low Temperature ◽  
Temperature Coefficient ◽  
Radiation Effects ◽  
Coefficient Of Thermal Expansion

scholarly journals A Proposal for a Composite with Temperature-Independent Thermophysical Properties: HfV2–HfV2O7

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5021
Author(s):  
Philipp Keuter ◽  
Anna L. Ravensburg ◽  
Marcus Hans ◽  
Soheil Karimi Aghda ◽  
Damian M. Holzapfel ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Temperature Coefficient ◽  
Thermophysical Properties ◽  
Coefficient Of Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Phase Fraction ◽  
Formation Temperature ◽  
Oxygen Mobility ◽  
Zero Temperature ◽  
Coefficient Of Elasticity

The HfV2–HfV2O7 composite is proposed as a material with potentially temperature-independent thermophysical properties due to the combination of anomalously increasing thermoelastic constants of HfV2 with the negative thermal expansion of HfV2O7. Based on literature data, the coexistence of both a near-zero temperature coefficient of elasticity and a coefficient of thermal expansion is suggested for a composite with a phase fraction of approximately 30 vol.% HfV2 and 70 vol.% HfV2O7. To produce HfV2–HfV2O7 composites, two synthesis pathways were investigated: (1) annealing of sputtered HfV2 films in air to form HfV2O7 oxide on the surface and (2) sputtering of HfV2O7/HfV2 bilayers. The high oxygen mobility in HfV2 is suggested to inhibit the formation of crystalline HfV2–HfV2O7 composites by annealing HfV2 in air due to oxygen-incorporation-induced amorphization of HfV2. Reducing the formation temperature of crystalline HfV2O7 from 550 °C, as obtained upon annealing, to 300 °C using reactive sputtering enables the synthesis of crystalline bilayered HfV2–HfV2O7.

Fabrication and Properties of W-SiCP/Cu Composites by Hot Pressing Sintering

2016 ◽  
Vol 697 ◽  
pp. 207-210
Author(s):  
Lian Meng Zhang ◽  
Yao Liu ◽  
Cheng Cheng Zhang ◽  
Guo Qiang Luo ◽  
Huang Liu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Low Temperature ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Hot Press ◽  
X Ray Diffraction ◽  
Ternary Composite ◽  
Hot Pressing Sintering ◽  
Hot Press Sintering ◽  
Structural Characterizations

Abstract. A new ternary composite of W-SiCP/Cu(40vol%) was designed and prepared by low-temperature hot-press sintering. The micro-structural characterizations were evaluated by X-ray diffraction (XRD) and scanning electron microstructure (SEM), coefficient of thermal expansion is measured. When sintered at 950°C-100MPa-2h, the relative density of the W-SiCP/Cu composites as a function of W content all exceeded 97%. Due to the plastic deformation of Cu, higher densification W-SiCP/Cu(40vol%) composites can be achieved at a relatively low temperature. The composites are characterized by the relatively low coefficient of thermal expansion, bending strength and hardness. The values of thermal expansion indicate that thermal expansion can be precisely controlled by adding SiC particles.

The Design and Use of Special-Purpose Attachments for the Horizontal Diffractometer

1963 ◽  
Vol 7 ◽  
pp. 302-313
Author(s):  
William L. Baun ◽  
John J. Renton
Keyword(s):  
Thermal Expansion ◽  
Low Temperature ◽  
Single Crystals ◽  
Low Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Semicrystalline Polymers ◽  
Organic Liquids ◽  
Crystalline Materials ◽  
Full Circle ◽  
Beryllium Window

AbstractSeveral special-purpose attachments have been designed and built for the Siemens horizontal diffractometer. Design details and experimental results are shown for the following equipment: (1) Low-temperature mount for poly crystalline materials—examples are shown illustrating identification of organic liquids crystallized at low temperatures, and results are presented on coefficient of thermal expansion of alloys in the binary system copper—platinum from −185 to 25°C. (2) Low-temperature mount for single-crystal studies—this design allows recording of higher-level layer lines by use of a domed beryllium window. Illustrations are shown for organic single crystals and for organic liquids crystallized in the lowtemperature mount. (3) Focusing attachment—this attachment uses a curved specimen mounted on the focusing circle (Seeman-Bohlin mounting). Comparisons of dispersion are made and examples such as the (400) reflection from molybdenum are shown using both curved and flat specimens. (4) Full-circle goniometer—this device has been used primarily for determining distribution of intensity in amorphous and semicrystalline polymers, but is applicable to study of single crystals. Examples of both of these applications are discussed.

The measuring approach of the nonlinear high-temperature coefficient of thermal expansion during isothermal cooling

Measurement ◽  
2020 ◽  
Vol 159 ◽  
pp. 107766
Author(s):  
Zujun Peng ◽  
Weihua Xie ◽  
Songhe Meng ◽  
Xinxing Han ◽  
Hongyue Wang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Temperature Coefficient ◽  
Coefficient Of Thermal Expansion
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