Elevated Temperature Fiber Push-Out Testing

1994 ◽  
Vol 365 ◽  
Author(s):  
J.I. Eldridge
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Experimental Procedure ◽  
Composite Systems ◽  
Test Methodology ◽  
Reinforced Composite ◽  
Critical Issues ◽  
Push Out ◽  
Potential Use

ABSTRACTThe potential use of fiber-reinforced composite materials for high temperature applications makes the development of interface test methodology at those high temperatures very desirable. A facility for performing high temperature fiber push-out tests will be described with emphasis on critical issues in experimental procedure. Examples from several composite systems illustrate the temperature dependence and environmental sensitivity of fiber debonding and sliding. Interpretation of the temperature dependence will be made primarily in terms of changes in residual stresses along with additional effects due to changes in matrix ductility and interfacial wear. Examples will show that high temperature fiber push-out testing can often distinguish between chemical and frictional fiber/matrix bonding in cases where room temperature only testing cannot.

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

Packaging Challenges for the Next Generation of Mobile Devices

2017 ◽  
Vol 2017 (S1) ◽  
pp. 000001-000023 ◽  
Author(s):  
Ahmer Syed
Keyword(s):  
Supply Chain ◽  
High Temperature ◽  
Mobile Applications ◽  
Room Temperature ◽  
Heat Dissipation ◽  
Stress Equation ◽  
Time To Market ◽  
Technology Innovations ◽  
Critical Issues ◽  
Die And Mold

Changes in board technology, denser packaging due to board size limitations, and phone thickness trends pose number of technical challenges for designing IC packages for mobile applications. While thin packages are required to meet height constraints requirements, room temperature co-planarity and high temperature warpage become critical issues for packages with thin substrate, die, and mold cap. Similarly, while PoP provides numerous benefits from size and business standpoint; heat dissipation and thickness constraints requires continuous development of new packaging technologies. In addition, changes in board behavior is affecting the overall stress equation, making Chip-Package-Board interaction very important when deciding chip and package level interconnections. This presentation will highlight some of these challenges and identify technology innovations in areas such as System in Package (SIP) to mitigating these factors while simplifying supply chain and improving overall time to market.

The Potential of Electronic High Temperature Devices Based Upon Polymer Derived Ceramics

2005 ◽  
Author(s):  
Weixing Xu ◽  
Jayanta Kapat ◽  
Louis C. Chow ◽  
Linan An ◽  
Wenge Zhang
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Room Temperature ◽  
Polymer Derived Ceramics ◽  
Micro Parts ◽  
Varied Composition ◽  
Potential Use ◽  
Lithography Technique ◽  
High Temperature Gas ◽  
Good Agreement

In this paper, we describe the potential use of polymer-derived ceramics (PDCs) for micro-sensors for high-temperature gas turbine applications. PDCs have several unique properties such as ease of microfabrication, excellent mechanical, materials and thermal properties, and tunable electrical conductivity. The electrical conductivity of PDCs with varied composition is measured as a function of temperature from room temperature upon to 700°C. Our results reveal that with suitable doping, the electrical conductivity could be controlled from insulating to semiconducting. Next, we measure the cure depth of the precursors as a function of UV intensity and exposure time. A model is developed to predict the cure depth as a function of photoinitiator concentration and light intensity. Good agreement between theory and experimental data is obtained. Finally, a few typical micro parts are fabricated by lithography technique.

Silicon Carbide Vertical JFET Operating at High Temperature

2008 ◽  
Vol 600-603 ◽  
pp. 1063-1066 ◽  
Author(s):  
Konstantin Vassilevski ◽  
Keith P. Hilton ◽  
Nicolas G. Wright ◽  
Michael J. Uren ◽  
A.G. Munday ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Temperature Dependence ◽  
Power Law ◽  
Current Density ◽  
Electron Mobility ◽  
Room Temperature ◽  
Protective Atmosphere ◽  
State Resistance ◽  
A Current

Trenched and implanted vertical JFETs (TI-VJFETs) with blocking voltages of 700 V were fabricated on commercial 4H-SiC epitaxial wafers. Vertical p+-n junctions were formed by aluminium implantation in sidewalls of strip-like mesa structures. Normally-on 4H-SiC TI-VJFETs had specific on-state resistance (RO-S ) of 8 mW×cm2 measured at room temperature. These devices operated reversibly at a current density of 100 A/cm2 whilst placed on a hot stage at temperature of 500 °C and without any protective atmosphere. The change of RO-S with temperature rising from 20 to 500 °C followed a power law (~ T 2.4) which is close to the temperature dependence of electron mobility in 4H-SiC.

Examination of CaO-Dy2O3 for potential use as a high-temperature transformation toughening System

1988 ◽  
Vol 46 ◽  
pp. 790-791
Author(s):  
M. M. Fleming ◽  
W. M. Kriven
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Transformation Toughening ◽  
Stabilized Zirconia ◽  
Two Phase ◽  
Volume Increase ◽  
Partially Stabilized Zirconia ◽  
Temperature Transformation ◽  
Fast Quenching ◽  
Potential Use

Similarities exist between the tetragonal to monoclinic transformation of ZrO2 and the monoclinic (B) to cubic (C) transformation of Dy2O3. On cooling the transformation occurs at 1950°C and is accompanied by an 8 % volume increase which causes shattering of bulk specimens. The transformation can be suppressed, however, by minor additions of CaO. An attempt was made to fabricate a “PSD” analogue to partially stabilized zirconia (PSZ).As-received and chemically precipitated powders of pure Dy2O3 were mixed with CaO (0 to 25 mol%), uniaxially and cold isostatically pressed, sealed in small Mo crucibles and sintered at various temperatures (1900° or 1650°C) and times before cooling or subsequent annealing treatments. Some pellets were annealed in the two phase (B + C) region at 1700°C for 2 hours before quenching. Specimens were examined by XRD, TEM, EDS, HVEM, and STEM.A fast quenching in combination with the =8 mol% CaO additions were found to be essential for retention of the high temperature B phase down to room temperature.

A Study of High Temperature DC and AC Gate Stressing on the Performance and Reliability of Power SiC MOSFETs

2013 ◽  
Vol 740-742 ◽  
pp. 549-552 ◽  
Author(s):  
Ronald Green ◽  
A.J. Lelis ◽  
M. El ◽  
Daniel B. Habersat
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
State Of The Art ◽  
Temperature Measurements ◽  
Voltage Instability ◽  
Test Methodology ◽  
Full Effect ◽  
Oxide Trap ◽  
Bias Temperature Stress ◽  
Trap Activation

Although high-temperature measurements show a dramatic reduction in the bias-temperature stress-induced threshold-voltage instability of present state-of-the-art devices, a more thorough test methodology shows that several different conclusions may actually be drawn. The particular conclusion depends on the specific post-BTS measurement technique employed. Immediate room-temperature measurements suggest that significant oxide-trap activation may still be occurring. A significant, yet rapid, post-BTS recovery is observed as well. These results underline the importance of making both high-temperature and room-temperature measurements, as a function of stress and recovery time, to better ensure that the full effect of the BTS is observed. Initial AC BTS results suggest a similar level of device degradation as occurs from a DC BTS.

Behavior of CSC-Type Shear Connectors under Pry-Out Shear Test: Analytical Study

2021 ◽  
Vol 1046 ◽  
pp. 45-58
Author(s):  
Xavier Fernando Hurtado ◽  
Maritzabel Molina
Keyword(s):  
Experimental Test ◽  
Numerical Models ◽  
Local Buckling ◽  
Concrete Slabs ◽  
Shear Connectors ◽  
Composite Systems ◽  
Test Methodology ◽  
Steel Shape ◽  
Cold Formed Steel ◽  
Push Out

The use of cold-formed steel (CFS) shapes in steel-concrete composite sections has increased over the past 20 years in the construction industry worldwide. This system has constructive advantages such as high load-bearing capacity, high stiffness and ductility, ease of transportation and assembly, and full usage of the capacity of the materials. Additionally, CFS sections are considered a sustainable alternative in construction.The capacity of the system depends on the effectiveness of shear connectors during the transfer of stress between materials. Currently, the push-out experimental test follows a standardized procedure to evaluate the capacity of shear connectors in composite sections, but CFS shapes have demonstrated premature failures by local buckling, thus questioning the applicability of the experimental test for such configurations.In this research, the capacity of the proposed confined shear connectors (CSC) is evaluated in composite systems, through the alternative pry-out test methodology. From numerical models, the effects of the steel shape thickness, the thickness of concrete slabs, the compressive strength of concrete and the separation between connectors in composite systems are studied. The analysis concluded that, under this test methodology, the separation between connectors does not represent statistically significant changes in the final capacity of the composite system.

B2 Alulinides for High Temperature Applications

1986 ◽  
Vol 81 ◽  
Author(s):  
K. Vedula ◽  
J.R. Stephes
Keyword(s):  
High Temperature ◽  
Nickel Aluminide ◽  
Titanium Aluminides ◽  
Research Center ◽  
Nasa Lewis Research ◽  
Aerospace Materials ◽  
Composite Systems ◽  
Reinforced Composite ◽  
Structural Applications ◽  
Titanium Nickel

The B2 aluminides are currently being investigated for potential high temperature structural applications. Although they are not being as actively pursued as the titanium aluminides or the L12 nickel aluminide, the B2 aluminides are very attractive from density gonsiderations. Several recent reviews of the potential for aluminides are available in literature [e.g Ref. 1,2]. Table I is a comparison of the titanium, nickel and iron aluminides of interest and shows that B2 NiAl and FeAl have the major advantage of lower densities than Ni3Al and Fe3Al. In addition, the melting point of NiAl is over 200K higher than convetitional nickel based superalloys. Hence, although low density is the prime driving force, at least in NiAl a temperature advantage is also possible. Both of these aluminides have the advantage of containing very inexpensive elements. In fact, the thrust towards the B2 aluminides evolved from a program aimed at conserving strategic aerospace materials at NASA Lewis Research Center. A recent thrust at NASA Lewis Research Center has been to consider these aluminides as matrix materials for fiber reinforced composite systems.

Effects of Alloying Elements on the Temperature Dependence of Yield Stress in L12-Co3(Al,W)

2015 ◽  
Vol 1760 ◽  
Author(s):  
Zhenghao M. T. Chin ◽  
Norihiko L. Okamoto ◽  
Haruyuki Inui
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Room Temperature ◽  
Single Phase ◽  
Alloying Elements ◽  
High Temperature Strength ◽  
Positive Temperature ◽  
Compression Tests ◽  
Polycrystalline Alloys

ABSTRACTThe effects of alloying elements (Ni/Ta) on the temperature dependence of yield stress in Co3(Al,W) with the L12 structure have been investigated through compression tests of nearly single-phase polycrystalline alloys in the temperature range between room temperature to 1,473K. Compared with a ternary Co3(Al,W), a Ni/Ta-added Co3(Al,W) alloy exhibits a higher γ΄ solvus temperature and lower onset temperature of the yield stress anomaly (positive temperature dependence of yield stress), suggesting that the CSF energy is increased by Ni/Ta addition. As a consequence, the high-temperature strength in Co3(Al,W) is considerably enhanced.

scholarly journals PDF calculations from STOE STADI P Ag Kα1 low- and high-temperature data

2014 ◽  
Vol 70 (a1) ◽  
pp. C1807-C1807
Author(s):  
Lothar Fink ◽  
Nicole Rademacher ◽  
Thomas Hartmann
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Temperature Data ◽  
Laboratory Setup ◽  
High Temperature Data ◽  
Chip Size ◽  
Peak Widths ◽  
Similar Peak

An impressive comparison of G(r) calculated with PDFgetX2(1) from data of Naphthalen taken at room temperature with a Stoe Stadi P powder diffractometer in Transmission mode equipped with a Ag-tube, a Ge(111)-monochromator for pure Ag-Kα1-radiation (0.5594 Å) as well as the Dectris MYTHEN 1K with1mm chip size and from synchrotron data, beamline X17A, NSLS Brookhaven with a wavelength of 0.1839 Å, yields amazingly similar peak widths for both experiment sites. To observe the temperature dependence of this resolution, the same laboratory setup with an additional Oxford Cryosystems Cobra or a Stoe furnace has been chosen to compare the signal width as a function of T. Low temperature data for these PDF calculation experiments has been taken from LaB6 as a crystalline standard and Naphthalene as well known organic phase. In addition high temperature G(r)-data from Ammonium Nitride will be demonstrated.

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