High-temperature friction characteristics of N-BK7 glass and their correlation with viscoelastic loss modulus

2021 ◽  
Author(s):  
Jian Zhou ◽  
Hongkun Xu ◽  
Chenyu Zhu ◽  
Wentao Ai ◽  
Xiaojun Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Loss Modulus ◽  
Friction Characteristics ◽  
Bk7 Glass

scholarly journals Friction Characteristics of Hardfacing Materials in High Temperature Sodium

1980 ◽  
Vol 44 (5) ◽  
pp. 479-486
Author(s):  
Syotaro Mizobuchi ◽  
Shigeki Kano ◽  
Kohichi Nakayama ◽  
Hideo Atsumo
Keyword(s):  
High Temperature ◽  
Friction Characteristics

Recycling of Plastic and Rubber Tire Waste in Asphalt Pavements

1994 ◽  
Vol 344 ◽  
Author(s):  
Geoffrey R. Morrison ◽  
Nolan K. Lee ◽  
Simon A.M. Hesp
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Low Temperature ◽  
Local Governments ◽  
Complex Modulus ◽  
Loss Modulus ◽  
Crumb Rubber ◽  
Asphalt Binders ◽  
Rubber Tire ◽  
Temperature Fracture

AbstractThis paper discusses some important issues related to the use of recycled thermoplastics and rubber tire waste in asphalt binders for hot-mix pavements. Both high temperature rheological and low temperature fracture studies are presented on recycled polyethylene, devulcanized and crumb rubber-modified asphalt binders. The results are compared to unmodified and commercially available modified binders. This research is especially timely in light of the U.S. Intermodal Surface Transportation Efficiency Act of 1991, Section 1038 which, starting in 1995, will force state and local governments to use significant amounts of recycled rubber tire or plastic waste in federally funded highway projects.High temperature rheological measurements of the loss modulus, loss tangent and complex modulus show a significant improvement when only small quantities of crumb rubber, devulcanized crumb rubber or waste polyethylene are added to the asphalt binders.The low temperature fracture performance of the modified asphalts is greatly influenced by the interfacial strength between the dispersed and continuous phase. The fracture toughness increases dramatically, only when low molecular weight polymers are grafted in-situ onto the rubber and polymer dispersed phases in order to strengthen the interface. This points to a crack-pinning mechanism as being responsible for the dramatic increase in fracture toughness that is observed in this work. Single phase, devulcanized crumb rubber-asphalt systems perform quite poorly at low temperatures.

Analysis of Effects of High Temperature on Asphalt Binder

2013 ◽  
Vol 325-326 ◽  
pp. 97-101
Author(s):  
Phu Cuong Cao ◽  
Zhong Yin Guo ◽  
Yong Shun Yang ◽  
Zhi Chao Xue
Keyword(s):  
High Temperature ◽  
Complex Modulus ◽  
Loss Modulus ◽  
Asphalt Binder ◽  
Great Influence ◽  
Complex Viscosity ◽  
Modified Asphalt ◽  
Resistance Parameter ◽  
Variation Of Parameters ◽  
Sbs Modified Asphalt

The study of effects of high temperature on asphalt binder based on viscoelasticity theory will help clarify the influence mechanism of temperature on asphalt binder. Based on the theory of viscoelasticity, the Dynamic Shear Rheology test is used as study method. The objective of this study is to analyze and determine the features of asphalt binder under the effect of high temperature. Meanwhile, study subjects are AH70 asphalt, SBS modified asphalt and MAC modified asphalt. The result indicates that temperature increases have great influence on asphalt binder, which are shown by the variation of parameters quickly decrease. The relationship between temperature and such parameters as complex modulus, storage modulus, loss modulus, complex viscosity, storage viscosity, loss viscosity, rutting resistance parameter and fatigue resistance parameter can be described as regression of power function.

Property Evolution and Reliability of Underfills Under Sustained High Temperature Storage

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Madhu Kasturi ◽  
Haotian Wu ◽  
Jeff Suhling ◽  
Edward Davis
Keyword(s):  
High Temperature ◽  
Loss Modulus ◽  
Viscoelastic Behavior ◽  
Relaxation Modulus ◽  
Dynamic Mechanical Properties ◽  
Master Curves ◽  
Dynamic Mechanical ◽  
Point Bend ◽  
Tan Δ ◽  
Impact Reliability

Abstract Automotive underhood electronics may be exposed to high temperature in the neighborhood of 100°C–200°C. Property evolution may impact reliability and accuracy of predictive models to assure desired use life. In this paper, evolution of properties of two underfill material properties are studied using DMA (Dynamic Mechanical Analyzer). The underfills are exposed to three different operational temperatures in the range of 100°C to 140°C for the measurements. The dynamic mechanical properties such as storage modulus (E′), loss modulus (E″), tangent delta (tan δ), and respective glass transition temperatures (Tg) are studied using DMA. Study of viscoelastic behavior of underfills is achieved by performing TTS (time-temperature superposition) experiments at 7 discrete frequencies 0.1, 0.21, 0.46, 1, 2.15, 4.64, and 10 Hz using DMA in three-point bend mode. From the selected reference temperatures, the master curves were constructed for storage moduli, loss moduli and tan delta as a function of frequency using TTS results. Using the WLF (Williams-Landel-Ferry) equation, the shift factors as a function of temperature were determined along the frequency axis. The relaxation modulus as a function of temperature and time can be obtained using the master curves of storage and loss moduli. A simple and detailed procedure has been established to find the Prony series constants.

Evolution of Prony Parameters for Underfills Subjected to High Temperature Long Term Aging

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Yunli Zhang ◽  
Haotian Wu ◽  
Jeff Suhling ◽  
Edward Davis
Keyword(s):  
High Temperature ◽  
Power Systems ◽  
Flip Chip ◽  
Loss Modulus ◽  
Viscoelastic Behavior ◽  
Aging Effect ◽  
Ball Grid Arrays ◽  
Different Temperatures ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic

Abstract Advanced drive assist systems and support power systems reside underhood where operating temperatures are much higher than in traditional consumer applications. Temperatures in automotive underhood electronics may range from −40 °C to +150°C for long periods of time during operation. Much of the advanced functionality is enable through the use of advanced architectures including flip-chip ball-grid arrays. Underfills are used to enhance the solder joint reliability between the chip and the substrate. However, there is insufficient information about the viscoelasticity of Underfills stored in sustained high temperature for long period of time. In this paper, two different types of Underfills have been cured and aged under two different temperatures: 100 °C and 150 °C. Multi-frequency scan dynamic mechanical analyzer (DMA) test has been conducted to study the viscoelasticity evolution from pristine, 30 days, 60 days, 90 days and 120 days. The master curve has been obtained and the pony pairs of UFs have been calculated. The linear viscoelastic behavior of two kinds of Underfills as the function of aging time and aging temperature has been investigated. Elastic modulus, loss modulus and glass transition temperature are extracted from the results of dynamic loading tests. The aging effect of linear viscoelasticity has been discussed.

High Temperature Resistance of Epoxy Adhesives under the Room-Temperature Curing

2011 ◽  
Vol 284-286 ◽  
pp. 1804-1807 ◽  
Author(s):  
De Long Ran ◽  
Jian Jun Xie ◽  
Kai Huang ◽  
Shui Ping Yin ◽  
Sheng Ming Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Absorption Band ◽  
Epoxy Resin ◽  
Room Temperature ◽  
Loss Modulus ◽  
Technological Parameters ◽  
Temperature Resistance ◽  
Epoxy Adhesives ◽  
High Temperature Resistance ◽  
Long Chain

High-temperature resistant epoxy adhesives cured under room-temperature becomes more and more important in many industries such as aerospace and aviation, the locomotive and diesel, etc. In this paper three self-made amine-based mannich-amide was mixed with E-44 epoxy resin under the same technological parameters, and the epoxy adhesives cured by the three amine-based mannich-amides under room-temperature are tested by FTIR, TGA and DMA. Results of TGA show a quicker drop in weight occurrence within 150-250°C for epoxy networks cured by multiamine-based mannich amides than the long-chain alkyl one. Results of FTIR show completely curing of epoxy adhesives cured by mannich amides under room temperature and the height of absorption band 1502cm-1(C-N) is much lower after 12h under 150°C,200°C atmosphere than 25°C. Results of DMA show that the Tg determined by DMA has an order EP AN2(89.9°C) >EP AN1(89.7°C)>EP AN3(80.8°C). In the rest results of DMA, the EP-AN3 system has the biggest storage modulus (E’) within 100-150°C while the EP-AN3 system has the smallest loss modulus(E”) within 100-150°C. As a whole, the epoxy adhesives cured by AN3 under room-temperature have the best high temperature resistance.

scholarly journals Rheological survey of carbon fiber-reinforced high-temperature thermoplastics for big area additive manufacturing tooling applications

2019 ◽  
pp. 089270571987394 ◽  
Author(s):  
Christine Ajinjeru ◽  
Vidya Kishore ◽  
Xun Chen ◽  
Christopher Hershey ◽  
John Lindahl ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Formation Process ◽  
Loss Modulus ◽  
Polyphenylene Sulfide ◽  
Oak Ridge ◽  
Bead Formation ◽  
Structural Applications

Carbon fiber (CF)-reinforced thermoplastic composites have been widely used in different structural applications due to their superior thermal and mechanical properties. The big area additive manufacturing (BAAM) system, developed at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility, has been used to manufacture several composite components, demonstration vehicles, molds, and dies. These components have been designed and fabricated using various CF-reinforced thermoplastics. In this study, the dynamic rheological and mechanical properties of a material commonly used in additive manufacturing, 20 wt% CF-acrylonitrile butadiene styrene (ABS), as well as three CF-reinforced high-temperature polymers, 25 wt% CF-polyphenylsulfone (PPSU), 35 wt% CF-polyethersulfone (PES), and 40 wt% CF-polyphenylene sulfide (PPS), used to print molds were investigated. The viscoelastic properties, namely storage modulus, loss modulus, tan delta, and complex viscosity, of these composites were studied, and the rheological behavior was related to the BAAM extrusion and bead formation process. The results showed 20 wt% CF-ABS and 40 wt% CF-PPS to display a more dominant elastic component at all frequencies tested while 25 wt% CF-PPSU and 35 wt% CF-PES have a more dominant viscous component. This viscoelastic behavior is then used to inform the deposition and bead formation process during extrusion on the BAAM system.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

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.

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