Evaluation of a New Low Thermal Expansion Creep Resistant Nickel-Based Alloy

2007 ◽  
Author(s):  
Paul D. Jablonski ◽  
Karol K. Schrems
Keyword(s):  
Power Generation ◽  
Thermal Expansion ◽  
Large Scale ◽  
Thermal Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Ferritic Steels ◽  
Chemical Processing ◽  
Large Scale Systems ◽  
Low Thermal Expansion ◽  
Nickel Based Alloy

For many large-scale systems such as land-based power generation and chemical processing facilities, stresses due to thermal expansion can become a significant consideration in system design. Additionally, differential thermal stresses result from materials such as ferritic steels used in conjunction with nickel-based superalloys. An experimental nickel-based alloy designed for low CTE (Coefficient of Thermal Expansion) has been evaluated for creep performance and is compared to other low CTE nickel-based alloys. The creep results of this new alloy compare favorably to other low CTE nickel-based alloys.

Highly transparent polyhydroxyimide/TiO2 and ZrO2 hybrid films with high glass transition temperature (Tg) and low coefficient of thermal expansion (CTE) for optoelectronic application

2017 ◽  
Vol 5 (33) ◽  
pp. 8444-8453 ◽  
Author(s):  
Shun-Wen Cheng ◽  
Tzu-Tien Huang ◽  
Chia-Liang Tsai ◽  
Guey-Sheng Liou
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermal Expansion Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
High Glass Transition Temperature ◽  
Hybrid Films ◽  
Optoelectronic Application ◽  
Low Thermal Expansion

Highly transparent polyhydroxyimide/TiO2 and ZrO2 hybrids films with high glass transition temperature and low thermal expansion coefficient for optoelectronic application.

Influence of Coating Layer to Reduce Thermal Stresses in Cylindrically Formed Metal Matrix Composites

2000 ◽  
Author(s):  
Fuat Okumus ◽  
Aydin Turgut ◽  
Erol Sancaktar
Keyword(s):  
Thermal Expansion ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Thermal Stresses ◽  
Coating Layer ◽  
Coefficient Of Thermal Expansion ◽  
Aluminum Matrix ◽  
Matrix Composites ◽  
Cylinder Model ◽  
Matrix Layer

Abstract In this study, the use of coating layers is investigated to reduce thermal stresses in the metal matrix composites which have a mismatch in coefficients of thermal expansions in fiber and matrix components. The thermoelastic solutions are obtained based on a three-cylinder model. It is shown that the effectiveness of the layer can be defined by the product of its coefficient of thermal expansion and thickness. Consequently, a compensating layer with a sufficiently high coefficient of thermal expansion can reduce the thermal stresses in the metal matrix. The study is based on a concentric three cylinder model isolating individual steel fibers surrounded with a coating layer and an aluminum matrix layer. Only monotonic cooling is studied.

Modification of Porous Cordierite Ceramic

2016 ◽  
Vol 721 ◽  
pp. 322-326
Author(s):  
Ruta Švinka ◽  
Visvaldis Svinka ◽  
Julija Bobrovik
Keyword(s):  
Compressive Strength ◽  
Thermal Expansion ◽  
Large Scale ◽  
Sintering Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Slip Casting ◽  
Concentrated Suspension ◽  
Cordierite Ceramic ◽  
Silica Additive ◽  
Porous Cordierite

Highly porous cordierite ceramic by using of talcum, kaolinite and γ-alumina was obtained by method of slip casting of concentrated suspension. Additives of amorphous silica and non-stabilized zirconia in the amount of 5 wt% were used. Sintering temperature of dried samples was in range of 1250 – 1450°C. All the samples contain crystalline phases of cordierite, mullite and corundum but, depending on the additives, as a result of sintering in addition forms spinel, cristobalite or zircon (ZrSiO4). Porosity of obtained materials changes in large scale from 42 to 59 per cent; it is influenced by both sintering temperature and composition. Compressive strength increases with the addition of zirconia. In comparison, compressive strength of samples without additives or with silica additive does not exceed 3.5 MPa. The increase of coefficient of thermal expansion depends both on the composition and sintering temperature. ZrO2 additive increases the coefficient of thermal expansion considerably.

A General Solution for the Elastoplastic Thermal Stresses in a Strain-Hardening Plate With Arbitrary Material Properties

1962 ◽  
Vol 29 (1) ◽  
pp. 151-158 ◽  
Author(s):  
A. Mendelson ◽  
S. W. Spero
Keyword(s):  
Thermal Expansion ◽  
General Solution ◽  
Strain Hardening ◽  
Material Properties ◽  
Thermal Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Stress And Strain ◽  
Linear Strain ◽  
Hardening Material ◽  
General Method

A general method is presented for obtaining the elastoplastic stress and strain distributions in a thermally stressed plate of a strain-hardening material with temperature-varying modulus, yield point, and coefficient of thermal expansion. It is shown that for linear strain-hardening the solution can often be obtained in closed form. It is indicated that the error due to neglecting strain-hardening may sometimes be appreciable. The assumption that the total strain remains the same as that computed elastically (strain invariance) often leads to smaller errors than the neglect of strain-hardening.

Development of Porous Material with High Young’s Modulus and Low Thermal Expansion Coefficient in SiC-Vitrified Bonding Material-LiAlSiO4 System

2009 ◽  
Vol 620-622 ◽  
pp. 715-718 ◽  
Author(s):  
Tatsuya Ono ◽  
Koji Matsumaru ◽  
Isaías Juárez-Ramírez ◽  
Leticia M. Torres-Martínez ◽  
Kozo Ishizaki
Keyword(s):  
Thermal Expansion ◽  
Porous Material ◽  
Porous Materials ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Large Scale ◽  
Young's Modulus ◽  
Negative Thermal Expansion ◽  
Low Thermal Expansion

Machines for manufacturing large scale flat displays are enlarging as the size of glasses increases. This work develops porous materials with a low thermal expansion coefficient and a high Young’s modulus. SiC and LiAlSiO4 were used for a positive and a negative thermal expansion materials, respectively. Compositions of powders for porous materials were determined to obtain a desirable Young’s modulus and thermal expansion coefficient by using SiC-VBM-LiAlSiO4 phase diagram at 20 % of porosity. The empirical values of Young’s modulus and a thermal expansion coefficient are close to the theoretical values by using the diagram. Fabricated porous material had high enough Young’s modulus of 87 GPa, and low enough thermal expansion coefficient of 2 x 10-6 K-1 at temperatures ranging from -17 °C to 190 °C with 22 % of porosity.

Fabrication and Characterization of Low Thermal Expansion Cordierite/Spodumene/Mullite Composite Ceramic for Cookware

2018 ◽  
Vol 766 ◽  
pp. 276-281
Author(s):  
Pranee Junlar ◽  
Thanakorn Wasanapiarnpong ◽  
Lada Punsukmtana ◽  
Noppasint Jiraborvornpongsa
Keyword(s):  
Thermal Expansion ◽  
Water Absorption ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Coefficient Of Thermal Expansion ◽  
Slip Casting ◽  
Ceramic Composites ◽  
Modulus Of Rupture ◽  
Mullite Phase ◽  
Low Thermal Expansion

Ceramic cookware can be taken a direct flame or stove top for the duration without damage. The selected materials must have low thermal expansion coefficient, high strength, low water absorption and high thermal shock resistance, reasonable in cost and easy to be produced. Cordierite and spodumene composite has been interested for ceramic cookware due to their fitted properties. In previous work, study in the cordierite-spodumene composite with low thermal expansion coefficient of 2.60 x 10-6 /°C when sintered at 1250 oC with a ratio of spodumene 60 wt% and cordierite 40 wt% can withstand the pot shape samples. However, the sample showed relatively high water absorption and low strength which was not appropriate for using in this application. In this research, mullite is added in the formula to improve strength and densification of ceramic composites. Spodumene, ball clay, calcined talc and calcined alumina are used as starting raw materials and formed by slip casting. All samples are sintered in a temperature range from 1250-1275 °C in an electric furnace. Water absorption and bulk density were tested by Archimedes method, modulus of rupture was tested by the three-point bending method, microstructure were investigated by SEM and the coefficient of thermal expansion was measured by dilatometer. It was found that the mullite phase was investigated when adding mullite more than 30 wt% in cordierite-spodumene composite.

Synthesis and processing of nanocrystalline Ag–Fe–Ni for low thermal expansion–high conductivity thermal management applications

2001 ◽  
Vol 16 (2) ◽  
pp. 340-343 ◽  
Author(s):  
J. Stolk ◽  
M. Gross ◽  
D. Stolk ◽  
A. Manthiram
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Metal Ion ◽  
Coefficient Of Thermal Expansion ◽  
Thermomechanical Analysis ◽  
Nominal Composition ◽  
Two Phase ◽  
X Ray ◽  
Fine Grained ◽  
Low Thermal Expansion

Nanocrystalline Ag–Fe–Ni powders were produced by a reduction of the aqueous metal ion solutions with sodium borohydride and then converted to fine-grained silver–Invar alloys that offer attractive thermal, electrical, and mechanical properties. The samples were characterized by x-ray diffraction, scanning electron microscopy, wavelength dispersive x-ray spectrometry, thermomechanical analysis, microhardness measurements, and electrical conductivity measurements; thermal conductivity was estimated using the Wiedemann–Franz law. Sintering of a specimen with a nominal composition of 60 wt% Ag–25.6 wt% Fe–14.4 wt.% Ni led to the formation of a two-phase silver–Invar alloy with a grain size of approximately 2 μm, a hardness of 133 HK200g, coefficient of thermal expansion of 12.44 × 10−6 / °C, and electrical conductivity of 2.13 × 105 (Ω cm) −1.

Mechanical Properties and Thermal Expansion Characteristics of Low Thermal Expansion Ductile Cast Iron with same Nickel Equivalent (NiE)

2010 ◽  
Vol 457 ◽  
pp. 380-385
Author(s):  
Minoru Hatate ◽  
Tohru Nobuki ◽  
Shoji Kiguchi ◽  
Kazumichi Shimizu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Thermal Expansion ◽  
Cast Iron ◽  
Coefficient Of Thermal Expansion ◽  
Solution Treatment ◽  
Ductile Cast Iron ◽  
High Dimensional ◽  
Cast Irons ◽  
Low Thermal Expansion

Low thermal expansion ductile cast iron is expected to become a new structural material with high dimensional stability against temperature change. We tried to develop a new low thermal expansion ductile cast iron by means of adding C and Si to Superinver alloy. In this study we prepared four kinds of ductile cast irons whose Co contents vary from 0% to 12 %, and investigated about the effects of Co content and solution-treatments on several main characteristics such as coefficient of thermal expansion and mechanical properties. The results obtained are as follows: With increase of Co content the amount of martensite increases but this martensite can be inverse-transformed to austenite totally or greatly by solution-treatment followed with water-quenching. In the case of Co content less than some 9 % the ability of relatively larger plastic deformation can be expected in inverse-transformed austenite.

Design of a Clamp for a Thermoelectric Generator Using Bimetallic Thermal Properties

2016 ◽  
Author(s):  
Robert Dell ◽  
C. S. Wei ◽  
Nicholas Mitchell ◽  
Runar Unnthorsson
Keyword(s):  
Power Generation ◽  
Thermal Expansion ◽  
Thermoelectric Power ◽  
Coefficient Of Thermal Expansion ◽  
Hot Water ◽  
Leaf Spring ◽  
Generation System ◽  
Thermoelectric Power Generation ◽  
Design Concepts ◽  
Power Generation System

A design team at the Cooper Union for the advancement of Science and Art has developed and patented a robust thermoelectric-based point of use power generation system with no moving parts that is designed to be clamped onto the outer wall of a steam or hot water pipe [1]. Furthermore, in 2013 The Cooper Union for the Advancement of Science received patents for The Bimetallic Leaf Spring and Clamping Device which was designed so that it can compensate for the expected positive expansion and contraction of the thermoelectric power generation system. This paper presents different design concepts evaluated during the development of the clamp and theoretical models for determining the coefficient of thermal expansion of the design concepts. Furthermore, the paper presents experimental results from testing different variations of the selected design concept. Finally, a theoretical thermal expansion model with experimentally obtained parameters is presented. The final clamp design compensates for the expansion and contraction of the thermoelectric power generation system.

Advanced Methodologies for Developing Improved Potted Smart Munitions for High-G Applications

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Nien-Hua Chao ◽  
John A. Dispenza ◽  
Mario DeAngelis
Keyword(s):  
Thermal Expansion ◽  
Thermal Management ◽  
Thermal Stresses ◽  
Coefficient Of Thermal Expansion ◽  
Barrier Properties ◽  
Temperature Cycling ◽  
Circuit Board ◽  
Polymer Layer ◽  
Interference Control ◽  
Protective Polymer

Potted electronics are becoming more common in precision-guided smart munitions designs due to the requirements for miniaturization and structural-robustness. In most of these applications, the potted electronics are inactive for most of their lifetime and may be stored without environmental (temperature and humidity) controls for up to 20 yr. The uncontrolled environment for smart munitions however makes the thermal management task especially difficult due to the coefficient of thermal expansion (CTE) mismatch that can exist between the potting material and the electronic components. In this paper, we will do the following: (1) present a methodology being developed for reducing the thermal stresses to the potted electronics used in uncontrolled environments by encapsulating the circuit board assembly (CBA) with a thin polymer layer which has been precisely formed to conform to the imprecisely shaped, as-populated, CBA. The protective polymer layer will be both flexible and soft enough to protect the CBA components from damage caused by thermal expansion mismatches, but not degrade the structural support that the potting provides during high-g force projectile launches, (2) discuss how the protective polymer layer methodology can also be used to lessen in-circuit board crosstalk, improve shielding from external RF interference, control tin-whisker growth, and enhance moisture barrier properties and thermal management for CBAs, and (3) demonstrate how to improve the smart munitions survivability under extreme high-g applications through the use of syntactic foams and material characterization before and after accelerated temperature-cycling and thermal-aging tests.

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