Investigation of Thermomechanical Properties of Low Temperature Cofired Ceramic

1994 ◽  
Vol 116 (2) ◽  
pp. 148-153
Author(s):  
J. M. Hu ◽  
D. Barker ◽  
R. Ghoshtagore ◽  
M. Pecht
Keyword(s):  
Low Temperature ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Thermomechanical Properties ◽  
Test Methods ◽  
Modulus Of Rupture ◽  
Multichip Modules ◽  
Electronic Packages ◽  
Ceramic Substrates ◽  
Design Models

Thermomechanical properties of low temperature cofired ceramic substrates in the range of operational temperatures are necessary to incorporate into the design models for multichip modules and other electronic packages. These properties are also required in assessing reliability and aiding in screening and qualification procedures. This paper presents the test methods and experimental results on various thermomechanical properties of low temperature cofired ceramic over the the temperature range of −55°C to +250°C. Material properties determined from the tests include the modulus of elasticity, the modulus of rupture, the fracture toughness, and the coefficient of thermal expansion.

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.

The Effect of the Thickness of the Low Temperature AlN Nucleation Layer on the Material Properties of GaN Grown on a Double-Step AlN Buffer Layer by the MOCVD Method

2015 ◽  
Vol 45 (2) ◽  
pp. 859-866 ◽  
Author(s):  
Wei-Ching Huang ◽  
Chung-Ming Chu ◽  
Chi-Feng Hsieh ◽  
Yuen-Yee Wong ◽  
Kai-wei Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Buffer Layer ◽  
Material Properties ◽  
Double Step ◽  
Nucleation Layer ◽  
Aln Buffer

Thermally Induced Delamination Buckling of a Thin Metal Layer on a Ceramic Substrate

2003 ◽  
Vol 125 (4) ◽  
pp. 512-519 ◽  
Author(s):  
C. J. Liu ◽  
L. J. Ernst ◽  
G. Wisse ◽  
G. Q. Zhang ◽  
M. Vervoort
Keyword(s):  
Failure Modes ◽  
Research Effort ◽  
Metal Layer ◽  
Electronic Packages ◽  
Ceramic Substrates ◽  
Thermally Induced ◽  
Thermal Expansion Coefficients ◽  
Interface Delamination ◽  
Delamination Buckling ◽  
Expansion Coefficients

Interface delamination failure caused by thermomechanical loading and mismatch of thermal expansion coefficients and other material properties is one of the important failure modes occurring in electronic packages, thus a threat for package reliability. To solve this problem, both academic institutions and industry have been spending tremendous research effort in order to understand the inherent failure mechanisms and to develop advanced and reliable experimental and simulation methodologies, thus to be able to predict and to avoid interface delamination before physical prototyping. Various damage mechanisms can be involved and can result in interface delamination phenomena. These are not all sufficiently addressed and/or reported so far, probably because of the complexities caused by the occurrence of strong geometric and materials nonlinearities. One of the phenomena being insufficiently understood so far is the so-called buckling-driven delamination of thin metalic layers on ceramic substrates. This phenomenon will be discussed in the present paper.

PREDICTION OF PEEK RESIN PROPERTIES FOR PROCESSING MODELING USING MOLECULAR DYNAMICS

2021 ◽  
Author(s):  
KHATEREH KASHMARI ◽  
PRATHAMESH DESHPANDE ◽  
SAGAR PATIL ◽  
SAGAR SHAH ◽  
MARIANNA MAIARU ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Residual Stresses ◽  
Crystallization Kinetics ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Processing Parameters ◽  
Thermomechanical Properties ◽  
Volumetric Shrinkage ◽  
Processing Temperature ◽  
Wide Range

Polymer Matrix Composites (PMCs) have been the subject of many recent studies due to their outstanding characteristics. For the processing of PMCs, a wide range of elevated temperatures is typically applied to the material, leading to the development of internal residual stresses during the final cool-down step. These residual stresses may lead to net shape deformations or internal damage. Also, volumetric shrinkage, and thus additional residual stresses, could be created during crystallization of the semi-crystalline thermoplastic matrix. Furthermore, the thermomechanical properties of semi-crystalline polymers are susceptible to the crystallinity content, which is tightly controlled by the processing parameters (processing temperature, temperature holding time) and material properties (melting and crystallization temperatures). Hence, it is vital to have a precise understanding of crystallization kinetics and its impact on the final component's performance to accurately predict induced residual stresses during the processing of these materials. To enable multi-scale process modeling of thermoplastic composites, molecular-level material properties must be determined for a wide range of crystallinity levels. In this study, the thermomechanical properties and volumetric shrinkage of the thermoplastic Poly Ether Ether Ketone (PEEK) resin are predicted as a function of crystallinity content and temperature using molecular dynamics (MD) modeling. Using crystallization-kinetics models, the thermo-mechanical properties are directly related to processing time and temperature. This research can ultimately predict the residual stress evolution in PEEK composites as a function of processing parameters.

scholarly journals Influence of Bitumen Type and Asphalt Mixture Composition on Low-Temperature Strength Properties According to Various Test Methods

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2118 ◽  
Author(s):  
Marek Pszczola ◽  
Cezary Szydlowski
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Cooling Rate ◽  
Strength Properties ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Mixture Composition ◽  
Tension Stress ◽  
Strength Reserve

In regions with low-temperatures, action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties of asphalt mixtures: tensile strength was measured using the thermal stress restrained specimen test (TSRST) and the uniaxial tension stress test (UTST), flexural strength was measured using the bending beam test (BBT), and fracture toughness was measured using the semi-circular bending test (SCB). The strength reserve behavior of tested asphalt mixtures was assessed as well. The influence of cooling rate on the strength reserve was investigated and correlations between results from different test methods were also analyzed and discussed. It was observed that the type of bitumen was a factor of crucial importance to low-temperature properties of the tested asphalt concretes. This conclusion was valid for all test methods that were used. It was also observed that the level of cooling rate influenced the strength reserve and, in consequence, resistance to low-temperature cracking. It was concluded that reasonably good correlations were observed between strength results for the UTST, BBT, and SCB test methods.

scholarly journals Nanostructured Bitumen with Nanocarbon

2019 ◽  
Vol 21 (4) ◽  
pp. 317 ◽  
Author(s):  
B.B. Teltayev ◽  
A.A. Kalybai ◽  
G.G. Izmailova ◽  
S.R. Rossi ◽  
E.D. Amirbayev ◽  
...  
Keyword(s):  
Low Temperature ◽  
Test Methods ◽  
Structure Variation ◽  
Temperature Resistance ◽  
Chemical Indicators ◽  
Excess Surface ◽  
The Cost ◽  
Physical And Chemical ◽  
Low Temperature Resistance

Physical and chemical indicators of bitumen quality of grade BND 70/100 with the added carbon nanopowder 2% by weight have been studied by laboratory test methods and analysis. High reaction ability of nanopowder particles and concentration of excess surface and internal energy in them have been determined, which provide the increase of low-temperature resistance, aggregate strength, and improvement of rheological properties of nanostructured bitumen. Essential structure variation has been proved: the increase of asphaltenes and oils content for 9% and 7.2% respectively due to the decrease of resins for 16.2% by weight. Methods have been discussed for preparing a liquid nanocarbon mix, adding of the mix into bitumen and homogenization of the bitumen. Some economic indicators have been represented which influence essentially the reduction for the cost value of the nanostructure bitumen.

scholarly journals Experimental study on the compression characteristics of soft soil based on low temperature effect

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Jian Zhang ◽  
◽  
Chunpeng Han ◽  
Jiayi Tian ◽  
Qingjie Dong ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phase Change ◽  
Compression Test ◽  
Variable Temperature ◽  
Soft Soil ◽  
Test Methods ◽  
Variable Load ◽  
Compression Tests ◽  
Different Temperatures ◽  
Freezing Condition

Based on the characteristics of long annual freezing time and short suitable construction period of soft soil in cold region, this paper discusses the feasibility of foundation treatment of soft soil in freezing-thawing layer under freezing condition. The deformation characteristics of soft soil in freezing-thawing layer in Hulunbuir area in China are studied by using two compression test methods, namely, constant temperature and variable load (CTVL) test, variable temperature and variable load (VTVL) test. The compressibility indexes under different temperatures and consolidation pressures are obtained. The research shows that the freezing-thawing soft soil has large compressibility, the maximum strain of CTVL test is 19.89%, and the maximum compression of VTVL test can reach 18.16%. The results of CTVL compression tests show that when the soil temperature is in the range of severe phase change (-1.5℃-0℃), the temperature change has the greatest influence on the compression coefficient of soil. The result of VTVL compression test shows that some additional deformation occurs under the action of low temperature. The additional deformation is further increased when the soil is under high consolidation pressure and in the severe phase change (-1.5℃-0℃).

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