scholarly journals The Influence of Impurity Content on Thermal Stability of Low Stacking Fault Energy Silver Processed by Severe Plastic Deformation

2012 ◽  
Vol 729 ◽  
pp. 222-227 ◽  
Author(s):  
Zoltán Hegedűs ◽  
Jenő Gubicza ◽  
Megumi Kawasaki ◽  
N.Q. Chinh ◽  
Z. Fogarassy ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Elevated Temperatures ◽  
Lattice Defect ◽  
Impurity Content ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Dislocation Loops ◽  
Boundary Frequency ◽  
Angular Pressing ◽  
Thermal Stability Of

The effect of the impurity content on the evolution of the ultrafine-grained (UFG) microstructure in low stacking fault energy Ag and its stability at room and elevated temperatures were investigated. Samples of silver having high (99.995%) and somewhat lower (99.99%) purity levels were processed by equal-channel angular pressing (ECAP) at room temperature (RT) up to 16 passes. Although, the minimum grain size achieved by ECAP was ~200 nm for both series, the lattice defect structure was strongly influenced by the impurity content. In the samples processed by 4-16 passes of ECAP a self-annealing occurred during storage RT that was promoted by the higher twin boundary frequency. Both room-and high-temperature thermal stability of 99.99% purity Ag were much better due to the pinning effect of impurities. It was found that a large number of dislocation loops remained in the microstructure even after recrystallization at high temperatures.

Thermal stability of sputtered copper films containing dilute insoluble tungsten: Thermal annealing study

2003 ◽  
Vol 18 (6) ◽  
pp. 1429-1434 ◽  
Author(s):  
C. H. Lin ◽  
J. P. Chu ◽  
T. Mahalingam ◽  
T. N. Lin ◽  
S. F. Wang
Keyword(s):  
Thermal Stability ◽  
Thermal Annealing ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Silicide Formation ◽  
Copper Silicide ◽  
Cu Films ◽  
Cu Film ◽  
Pure Cu ◽  
Thermal Stability Of

This paper describes studies on the thermal annealing behavior of Cu films with 2.3 at.% W deposited on Si substrates. The magnetron cosputtered Cu films with insoluble W were vacuum annealed at temperatures ranging from 200 to 800 °C. Twins were observed in focused ion beam and transmission electron microscopy images of as-deposited and 400 °C annealed pure Cu film, and these twins were attributed to the intrinsic low stacking fault energy. Twins in pure Cu film may provide an additional diffusion path during annealing for copper silicide formation. The beneficial effect of W on the thermal stability of Cu film was supported by the following observations: (i) x-ray diffraction studies show that Cu4Si was formed at 530 °C in Cu–W film, whereas pure Cu film exhibited Cu4Si growth at 400 °C; (ii) shallow diffusion profiles for Cu into Si in Cu–W film through secondary ion mass spectroscopy analyses, and the high activation energy needed for the copper silicide formation from the differential scanning calorimetry study; (iii) addition of W in Cu film increases the stacking fault energy and results in a low twin density.

scholarly journals Влияние термообработки на упругие и микропластические свойства ультрамелкозернистого титана с разным содержанием примесей

2019 ◽  
Vol 45 (22) ◽  
pp. 47
Author(s):  
Б.К. Кардашев ◽  
М.В. Нарыкова ◽  
В.И. Бетехтин ◽  
А.Г. Кадомцев ◽  
А.Ю. Токмачева-Колобова
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Elevated Temperatures ◽  
Impurity Content ◽  
Grain Sizes ◽  
Ultrafine Grained ◽  
Titanium Grade ◽  
Thermal Stability Of

The effect of elevated temperatures on elastic and microplastic properties of ultrafine-grained titanium prepared by severe plastic deformation is discussed. Three sets of a-titanium VT1-0, Grade-4 and PT3-V which differ each other in polycrystal structure and impurity content were investigated. As experiments show, significant changes in grain sizes, elastic and microplastic properties were observed only for the purest titanium VT1-0. The thermal stability of other sets of titanium (Grade-4 and PT3-V) was found to be better; it is explained by higher impurity content in these materials.

scholarly journals Thermal stability and diffusion characteristics of ultrathin amorphous carbon films grown on crystalline and nitrogenated silicon substrates by filtered cathodic vacuum arc deposition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shengxi Wang ◽  
Anurag Roy ◽  
Kyriakos Komvopoulos
Keyword(s):  
Thermal Stability ◽  
Amorphous Carbon ◽  
Silicon Substrate ◽  
Elevated Temperatures ◽  
Carbon Films ◽  
Vacuum Arc ◽  
Cross Sectional ◽  
Prolonged Heating ◽  
Filtered Cathodic Vacuum Arc ◽  
Thermal Stability Of

AbstractAmorphous carbon (a-C) films are widely used as protective overcoats in many technology sectors, principally due to their excellent thermophysical properties and chemical inertness. The growth and thermal stability of sub-5-nm-thick a-C films synthesized by filtered cathodic vacuum arc on pure (crystalline) and nitrogenated (amorphous) silicon substrate surfaces were investigated in this study. Samples of a-C/Si and a-C/SiNx/Si stacks were thermally annealed for various durations and subsequently characterized by high-resolution transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The TEM images confirmed the continuity and uniformity of the a-C films and the 5-nm-thick SiNx underlayer formed by silicon nitrogenation using radio-frequency sputtering. The EELS analysis of cross-sectional samples revealed the thermal stability of the a-C films and the efficacy of the SiNx underlayer to prevent carbon migration into the silicon substrate, even after prolonged heating. The obtained results provide insight into the important attributes of an underlayer in heated multilayered media for preventing elemental intermixing with the substrate, while preserving the structural stability of the a-C film at the stack surface. An important contribution of this investigation is the establishment of an experimental framework for accurately assessing the thermal stability and elemental diffusion in layered microstructures exposed to elevated temperatures.

scholarly journals Mechanical and thermal stability of retained austenite in plastically deformed bainite-based TRIP-aided medium-Mn steels

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Ulrich Krupp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Retained Austenite ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Cost Effective ◽  
Tensile Tests ◽  
Thermal Stability Of

AbstractAdvanced medium-Mn sheet steels show an opportunity for the development of cost-effective and light-weight automotive parts with improved safety and optimized environmental performance. These steels utilize the strain-induced martensitic transformation of metastable retained austenite to improve the strength–ductility balance. The improvement of mechanical performance is related to the tailored thermal and mechanical stabilities of retained austenite. The mechanical stability of retained austenite was estimated in static tensile tests over a wide temperature range from 20 °C to 200 °C. The thermal stability of retained austenite during heating at elevated temperatures was assessed by means of dilatometry. The phase composition and microstructure evolution were investigated by means of scanning electron microscopy, electron backscatter diffraction, X-ray diffraction and transmission electron microscopy techniques. It was shown that the retained austenite stability shows a pronounced temperature dependence and is also stimulated by the manganese addition in a 3–5% range.

Thermal Breakdown Kinetics of 1-Ethyl-3-Methylimidazolium Ethylsulfate Measured Using Quantitative Infrared Spectroscopy

2017 ◽  
Vol 71 (12) ◽  
pp. 2626-2631 ◽  
Author(s):  
Jeffrey L. Wheeler ◽  
McKinley Pugh ◽  
S. Jake Atkins ◽  
Jason M. Porter
Keyword(s):  
Thermal Stability ◽  
Room Temperature ◽  
Computational Models ◽  
Elevated Temperatures ◽  
Molar Absorptivity ◽  
Ir Absorption ◽  
Optical Cell ◽  
Multiple Samples ◽  
Kinetics Of ◽  
Thermal Stability Of

In this work, the thermal stability of the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4]) is investigated using infrared (IR) spectroscopy. Quantitative IR absorption spectral data are measured for heated [EMIM][EtSO4]. Spectra have been collected between 25 ℃ and 100 ℃ using a heated optical cell. Multiple samples and cell pathlengths are used to determine quantitative values for the molar absorptivity of [EMIM][EtSO4]. These results are compared to previous computational models of the ion pair. These quantitative spectra are used to measure the rate of thermal decomposition of [EMIM][EtSO4] at elevated temperatures. The spectroscopic measurements of the rate of decomposition show that thermogravimetric methods overestimate the thermal stability of [EMIM][EtSO4].

scholarly journals Thermal Stability of Residual Stresses in Differently Deep Rolled Surface Layers of Steel SAE 1045

2021 ◽  
Author(s):  
Stephanie Saalfeld ◽  
Thomas Wegener ◽  
Berthold Scholtes ◽  
Thomas Niendorf
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Residual Stresses ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Decisive Role ◽  
Deep Rolling ◽  
Material Conditions ◽  
The Stability ◽  
Thermal Stability Of

AbstractThe stability of compressive residual stresses generated by deep rolling plays a decisive role on the fatigue behavior of specimens and components, respectively. In this regard, deep rolling at elevated temperature has proven to be very effective in stabilizing residual stresses when fatigue analysis is conducted at ambient temperature. However, since residual stresses can be affected not only by plastic deformation but also when thermal energy is provided, it is necessary to analyze the influence of temperature and time on the relaxation behavior of residual stresses at elevated temperature. To evaluate the effect of deep rolling at elevated temperatures on stability limits under thermal as well as combined thermo-mechanical loads, the present work introduces and discusses the results of investigations on the thermal stability of residual stresses in differently deep rolled material conditions of the steel SAE 1045.

Thermal Stability of Ni40Ti40Nb20 and Ni32Ti48Nb20 Tapes Obtained by Rapid Solidification Technique

2012 ◽  
Vol 188 ◽  
pp. 41-45
Author(s):  
György Thalmaier ◽  
Ioan Vida-Simiti ◽  
N. Jumate ◽  
Viorel Aurel Şerban ◽  
C. Codrean ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Purity ◽  
Elevated Temperatures ◽  
Graphite Crucible ◽  
Argon Atmosphere ◽  
Membrane Reactors ◽  
Master Alloys ◽  
Selective Membrane ◽  
Dta Analysis ◽  
Thermal Stability Of

Nickel–titanium- group 5A metal (V, Nb, Ta, Zr) alloys are known as promising hydrogen-selective membrane materials. They can potentially be used in membrane reactors, which can produce high-purity H2 and CO2 streams from coal-derived syngas at elevated temperatures. The master alloys were prepared by arc melting using high purity metals in a Ti-gettered argon atmosphere. The alloys were melted several times in order to improve homogeneity. The ingots were induction-melted under a high-purity argon atmosphere in a quartz tube and graphite crucible injected through a nozzle onto a Cu wheel to produce rapidly solidified amorphous ribbons. Thermal stability of the Ni40Ti40Nb20 and Ni32Ti48Nb20 thin tapes has been examined using DTA analysis.

Thermal Stability of Magnetic Properties in Dehydrogenated Triarylmethane Resins

1989 ◽  
Vol 173 ◽  
Author(s):  
Michiya Otani ◽  
Sugio Otani
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
The Stability ◽  
Thermal Stability Of

ABSTRACTThe stability of the magnetic properties of dehydrogenated triaryl-methane resins was investigated both at room temperature and at elevated temperatures. A magnetic property different from that reported in a previous paper was found in the course of studying the reproducibility of synthesis. This new property was examined through a mechanical response of the resins to a set of permanent magnets.

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