Experimental Evaluation of Mechanical Behavior of GaAs Wafer Material

1991 ◽  
Vol 226 ◽  
Author(s):  
Jun Ming Hu ◽  
Michael Pecht ◽  
Donald Barker
Keyword(s):  
Stress Intensity Factor ◽  
Thermal Expansion ◽  
Mechanical Behavior ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Critical Value ◽  
Modulus Of Rupture ◽  
Gaas Wafer ◽  
Different Temperatures ◽  
Temperature Ranges

AbstractThe mechanical behavior of non-metalized GaAs wafer material at different temperatures were evaluated. The material properties of GaAs, including the modulus of elasticity, the modulus of rupture, the critical value of stress intensity factor, and the coefficient of thermal expansion, were experimentally determined over various temperature ranges.

Temperature Dependence of the Mechanical Properties of GaAs Wafers

1991 ◽  
Vol 113 (4) ◽  
pp. 331-336 ◽  
Author(s):  
Jun Ming Hu ◽  
Michael Pecht
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Critical Value ◽  
Modulus Of Rupture ◽  
Gaas Wafer ◽  
Photovoltaic Conversion Efficiency ◽  
Die Attach ◽  
Different Temperatures ◽  
Fracture Assessment

GaAs is known to have superior electronic properties and greater photovoltaic conversion efficiency compared to elemental semiconductors such as silicon and germaniumn. Mechanical properties of GaAs at different temperatures are now necessary to incorporate into the design models for the GaAs die attach and substrate architecture for microelectronic packages. These properties are also required to aid in defining reliability and screening specifications. This paper presents the experiment results on various material properties of GaAs wafer over the temperature range of − 75°C to 200°C. Material properties determined from testing include the modulus of elasticity, the modulus of rupture, the critical value of stress intensity factor, and the coefficient of thermal expansion. The importance of fracture assessment in semiconductor devices is also discussed.

Influence of Materials Properties on the Irradiation Behavior of U-10Mo Monolithic Mini-Plates

2015 ◽  
Author(s):  
Walid Mohamed ◽  
Hee Seok Roh
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Mechanical Behavior ◽  
Material Properties ◽  
Mechanical Response ◽  
Coefficient Of Thermal Expansion ◽  
Irradiation Creep ◽  
Mini Plate ◽  
Irradiation Behavior ◽  
Cladding Material

The DOE/NNSA Conversion [1] Program in the US aims to minimize the use of high enrichment uranium in civilian applications. This initiative is being approached by converting research and test reactors from the use of highly enriched uranium (HEU) to low enrichment uranium (LEU, <20% 235U) with high density of uranium to achieve stable operation of converted reactors. Among variety of fuel materials investigated to serve in the conversion process, U-Mo based alloys have shown stable and acceptable swelling response under typical operation conditions of research and test reactors. For the conversion of high performance research reactors, a large number of irradiation experiments were conducted to evaluate the mechanical behavior of the U-10Mo monolithic mini-plate; however, it is difficult to investigate all design and operation variables with potential impact on the irradiation behavior of the fuel experimentally. Thus, this study performed Finite Element Analyses (FEA) on a 3-D monolithic plate by changing material properties of components. The material properties considered in this study included thermal, mechanical, and irradiation specific properties of the fuel, cladding, and liner. Among FEA results, higher Young’s modulus of cladding material caused a significant decrease in all stress values in the three sections of the monolithic mini-plate. On the other hand, variation in the Young’s modulus of Zr-liner showed the minimal effect on the overall mechanical response of the monolithic mini-plate. Results showed that increasing the yield stress of the cladding material directly caused a increase in the maximum stress observed in the cladding section by almost 40 %. Considering the thermal properties of materials in the monolithic plate, maximum and minimum stress in fuel foil were found to either increase or decrease in proportional with the coefficient of thermal expansion of the fuel material. However, variation in the coefficient of thermal expansion in the cladding section caused a remarkable increase in peak stresses in the fuel foil. While mechanical and thermal properties of the foil, liner, and cladding sections are known, other irradiation-dependent properties such as coefficient of irradiation creep of U-10Mo are not firmly determined to date. The mechanical response of L1P756 is being simulated with different values of the coefficient of irradiation creep and the observed “bulging” in the plate will be compared to available post-irradiation measurements. Thus, it will be possible to determine an accurate value of irradiation creep coefficient of U-10Mo which in turn would allow predicting its mechanical behavior under different irradiation conditions.

scholarly journals EFFECT OF TEMPERATURE ON THE MECHANICAL BEHAVIOR OF THE HUMAN AORTA AND CAROTID ARTERIES

2021 ◽  
Vol 108 (Supplement_3) ◽  
Author(s):  
N Burgos Frías ◽  
R J Burgos Lázaro ◽  
J Rivas Oyarzabal ◽  
V Ospina Mosquera ◽  
F Rojo Pérez ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Internal Pressure ◽  
Mechanical Behavior ◽  
Coefficient Of Thermal Expansion ◽  
Chemical Activation ◽  
Passive State ◽  
Effect Of Temperature ◽  
Human Aorta ◽  
External Diameter ◽  
Different Temperatures

Abstract INTRODUCTION Temperature affects the mechanical behavior of the arteries, a fact that intervenes in their function, both in physiology and in pathological states. The aim of the study is to analyze the mechanical response in the arteries (aorta and carotids) to changes in temperature. MATERIAL AND METHODS The thermo-mechanical behavior of human arteries (26 primitive carotids and 26 thoracic aortas) from cadaveric organ donors has been studied. The tests were carried out in a passive state, without electrical or chemical activation of the vessels. Pressurization tests were carried out at 4 different temperatures (17, 27, 37 and 42ºC) correlating internal pressure-external diameter of the vessels. The thermo-mechanical analysis was evaluated using the pressure-diameter curves at different temperatures, for this the coefficient of thermal expansion (α = (ΔD / D) / ΔT) and the Hayashi stiffness (β), exponential equation (Pressure / Diameter ratio). RESULTS The effect of temperature on arterial behavior is maximum when the curves refer to the initial diameter of the vessel at 0 mmHg for each temperature. At low pressures, the coefficient of dilation is negative, while above a certain threshold pressure (different for each type of artery), the coefficient of dilation becomes positive. CONCLUSIONS The stiffness of the vessels is manifested in the slope of the pressure-diameter curves and decreases with increasing temperature. The coefficient of thermal expansion is a function of the internal pressure to which the arteries are subjected.

scholarly journals Characterizing the Performance of Ternary Concrete Mixtures Involving Slag and Metakaolin

2020 ◽  
Vol 5 (2) ◽  
pp. 14
Author(s):  
Matthew S. Sullivan ◽  
Mi G. Chorzepa ◽  
Stephan A. Durham
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Fly Ash ◽  
Coefficient Of Thermal Expansion ◽  
Drying Shrinkage ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Ternary Mixtures ◽  
Modulus Of Rupture ◽  
Ternary Blends

Ternary blends of cementitious materials are investigated. A cement replacement level of 45% is used for all ternary mixtures consisting of 15% metakaolin and 30% slag replacements. Three metakaolin and two blast furnace slag, referred to as ‘slag’ for short, products commercially available are used to compare performance in ternary blends. A mixture with a 45% fly ash replacement is included to serve as a benchmark for performance. The control mixture contains 422 kg of cement per cubic meter of concrete, and a water-to-cementitious material ratio of 0.43 is used for all mixtures with varying dosages of superplasticizer to retain workability. Mixtures are tested for mechanical properties, durability, and volumetric stability. Mechanical properties include compression, split-cylinder tension, modulus of rupture, and dynamic Young’s modulus. Durability measures are comprised of rapid chloride-ion penetrability, sulfate resistance, and alkali–silica reactivity. Finally, the measure of dimensional stability is assessed by conducting drying shrinkage and coefficient of thermal expansion tests. Results indicate that ternary mixtures including metakaolin perform similarly to the control with respect to mechanical strength. It is concluded that ternary blends perform significantly better than both control and fly ash benchmark in tests measuring durability. Furthermore, shrinkage is reduced while the coefficients of thermal expansion are slightly higher than control and the benchmark.

scholarly journals The Use of Recycled Carpet in Low-Cost Composite Tooling Materials

Recycling ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 12 ◽  
Author(s):  
Kunal Mishra ◽  
Sarat Das ◽  
Ranji Vaidyanathan
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Low Cost ◽  
Value Engineering ◽  
Compressive Properties ◽  
Structural Composites ◽  
Environmental Deterioration ◽  
Composite Tooling

More than 250,000 metric tons (600 million pounds) of carpet are dumped in landfills every year. That creates a significant concern regarding environmental deterioration and economic liability. It is therefore imperative to develop sustainable post-consumer carpet-based products for high-value engineering applications such as composite tooling. To be considered as an acceptable composite tooling material, the composite needs to meet certain required properties such as a low coefficient of thermal expansion, excellent compressive properties, and high a hardness value after repeated exposure to curing cycles. The tooling composites must also exhibit the ability to endure several curing cycles, without deteriorating the mechanical properties. In the present investigation, post-consumer carpet has been recycled in the form of structural composites for tooling applications. The recycled carpet composites have been reinforced with 0.5 wt.% of graphene nanoplatelets to modify the material properties of the carpet composites. The results from compressive and hardness experiments demonstrate that the recycled carpet preserved its mechanical integrity even after several curing cycles. This indicates that recycled carpet composites have the potential to be a low-cost composite tooling alternative for the industry.

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.

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.

Design of a Composite Encapsulation for Concentrated Photovoltaic Systems With Improved Performance

2019 ◽  
Author(s):  
Kabeer Raza ◽  
Syed Sohail Akhtar ◽  
Abul Fazal M. Arif ◽  
Abbas Saeed Hakeem
Keyword(s):  
Thermal Conductivity ◽  
Finite Element ◽  
Thermal Expansion ◽  
Shear Modulus ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Material Design ◽  
Element Model ◽  
Parametric Studies

Abstract Most of the currently used encapsulants are inefficient for cooled concentrated photovoltaic (CPV) systems. The encapsulant of cells for CPV systems, must have an optimum combination of thermal conductivity, coefficient of thermal expansion and long term shear modulus. In this work an improved backside composite encapsulation is designed and developed that can provide increased power output and longer life by enhancing the effectiveness of cooling and reducing thermal stresses. The best combination of material properties is identified through parametric studies on finite element model of CPV laminate using ethylene vinyl acetate as datum line. It is found that increasing thermal conductivity from 0.311 to 0.75 W/mK can improve the cooling and hence the power production by 2%. While long term shear modulus and coefficient of thermal expansion needs to be reduced for a longer service life. Using in-house built material design codes, optimum combinations of matrix and filler were identified that could provide the set range of properties. In line with material design code, a total of only four samples using thermoplastic polyurethane as matrix and Al2O3 or AlN as fillers were synthesized to validate the design experimentally. The material properties were measured and used in the parent finite element model to evaluate the performance of the experimentally developed material and to validate the parametric studies. A good agreement is found between the experimental and computational results and hence the overall methodology is found effective for application focused design and development of composite materials. It is expected that this material design and development approach will provide a useful guideline to the CPV manufacturing industries.

The Influence of the Material Properties on the Hydraulic Spool Valve's Viscous Temperature Rise

2013 ◽  
Vol 365-366 ◽  
pp. 277-280
Author(s):  
Jing Jiang Yan ◽  
Jian Ke ◽  
Huan Long Liu ◽  
Guo Zhi Wang ◽  
Da Hai Zhou
Keyword(s):  
Thermal Expansion ◽  
Temperature Rise ◽  
Material Properties ◽  
Hydraulic System ◽  
Thermal Deformation ◽  
Coefficient Of Thermal Expansion ◽  
Cfd Models ◽  
Spool Valve ◽  
Main Factor

Hydraulic spool valve is one of the important elements in the hydraulic system. Considering the material properties of the fluid and solid, CFD models of the viscous temperature rise was built and calculated with the spool material influence on the viscous temperature rise and thermal deformation. Analyzed: the viscosity of the fluid was the main factor affecting on temperature rise, while the coefficient of thermal expansion of the spool was also the main factor to affect the throttling temperature rise of the deformation.

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