Interaction between the third alloying element and the interfacial structure of AgCu-alloy brazed heterogeneous metal integration

2021 ◽  
pp. 160933
Author(s):  
Yaotian Yan ◽  
Tao Liu ◽  
Jinghuang Lin ◽  
Liang Qiao ◽  
Jinchun Tu ◽  
...  
Keyword(s):  
Interfacial Structure ◽  
Alloying Element ◽  
The Third

scholarly journals Influence of alloying elements on the thermal behavior of NiTi shape memory alloys

2021 ◽  
Vol 342 ◽  
pp. 06007
Author(s):  
Nicoleta-Monica Lohan ◽  
Çtefan-Lucian Toma ◽  
Mihai Popa ◽  
Alin Marian Cazac ◽  
Bogdan Pricop
Keyword(s):  
Shape Memory Alloys ◽  
Thermal Behavior ◽  
Shape Memory ◽  
Alloying Elements ◽  
Alloying Element ◽  
Scanning Calorimetry ◽  
Automotive Manufacturing ◽  
Niti Alloys ◽  
The Third ◽  
Niti Shape Memory Alloys

NiTi based shape memory alloys are one of the most intensely studied alloys from its class. Therefore, diverse commercial applications have been developed due to certain properties such as: shape memory effect, superelasticity and corrosion resistance. Currently, the main applications of NiTi alloys are automotive manufacturing and aerospace actuators, biomedical devices or pipe couplings. In recent years, NiTi shape memory alloys have been alloyed with a third element in order to improve the above-mentioned properties. In order to investigate the influence of the alloying elements on the thermal behavior of NiTi alloys, the addition of the third alloying element (Ta and Nb) is under investigation in the present study. The thermal behavior of the three alloys (NiTi, NiTiNb and NiTiTa) was studied by differential scanning calorimetry. Following the experiments, it was observed that the addition of the third alloying element influences the critical transformation temperatures.

Columnar to Equiaxed Transition in Al-Cu-Ag

2010 ◽  
Vol 649 ◽  
pp. 379-384 ◽  
Author(s):  
Els Nagels ◽  
Ludo Froyen
Keyword(s):  
Temperature Gradient ◽  
Ternary System ◽  
Cooling Rate ◽  
Binary Systems ◽  
Temperature Gradients ◽  
Alloying Element ◽  
The Third ◽  
Columnar To Equiaxed Transition ◽  
Lower Temperature

In this work the transition from columnar to equiaxed growth is studied during the solidification of the univariant eutectic L=> α(Al) + θ-Al2Cu in the ternary Al-Cu-Ag system. The columnar to equiaxed transition (CET) in a ternary system behaves very similar to the CET observed in binary systems [1]. It is observed that the CET occurs at lower temperature gradients when the amount of the third alloying element, in this case Ag, is increased. Another important solidification parameter is the cooling rate of the furnace. When the cooling rate is increased, the CET will occur at lower positions in the sample where the temperature gradient is lower.

scholarly journals Effect of the Addition of Molybdenum on the Structure and Corrosion Resistance of Zinc–Iron Plating

2017 ◽  
Author(s):  
Daichi Kosugi ◽  
Takeshi Hagio ◽  
Yuki Kamimoto ◽  
Ryoichi Ichino
Keyword(s):  
Corrosion Resistance ◽  
Surface Morphology ◽  
Electronic State ◽  
Extrapolation Method ◽  
Corrosion Performance ◽  
Alloying Element ◽  
High Corrosion Resistance ◽  
Promising Candidate ◽  
The Third ◽  
Iron Plating

Zn–Ni plating is indispensable in various industries because of its high corrosion resistance. However, Ni has been reported to trigger allergies; thus, an alternative Ni-free plating is desired. Zn–Fe plating is considered to be a promising candidate, albeit its corrosion resistance still needs to be improved. The corrosion resistance of Zn–Fe plating is expected to increase by the addition of Mo as the third alloying element as it is more noble than Zn and Fe. In this study, Zn–Fe–Mo plating with a corrosion resistance nearly equivalent to that of the Zn–Ni plating was fabricated. Zn–Fe–Mo plating was electrically deposited from continuously agitated plating baths prepared by mixing ZnSO4, FeSO4, Na2MoO4, Na3C6H5O7, and Na2SO4 using Fe or Ni plates as the substrate. The surface morphology, composition, crystal phase, and electronic state of Mo of the platings were investigated by SEM-EDS, XRD, and XPS. The anti-corrosion performance was evaluated by Tafel extrapolation method. Formation of plating comprising a Mo containing alloy phase was found to be crucial for improving corrosion resistance. The Zn–Fe–Mo plating demonstrates promise for replacing anti-corrosion Zn–Ni platings.

Progress report on 21-cm observations at low latitude between longitudes (l 11) 0° and 66°

1967 ◽  
Vol 31 ◽  
pp. 177-179
Author(s):  
W. W. Shane
Keyword(s):  
Preliminary Report ◽  
Progress Report ◽  
Galactic Centre ◽  
Low Latitude ◽  
The Third ◽  
Introductory Lecture ◽  
Centre Region

In the course of several 21-cm observing programmes being carried out by the Leiden Observatory with the 25-meter telescope at Dwingeloo, a fairly complete, though inhomogeneous, survey of the regionl11= 0° to 66° at low galactic latitudes is becoming available. The essential data on this survey are presented in Table 1. Oort (1967) has given a preliminary report on the first and third investigations. The third is discussed briefly by Kerr in his introductory lecture on the galactic centre region (Paper 42). Burton (1966) has published provisional results of the fifth investigation, and I have discussed the sixth in Paper 19. All of the observations listed in the table have been completed, but we plan to extend investigation 3 to a much finer grid of positions.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Monte Carlo Algorithms for Moments of Transition Arrays

1988 ◽  
Vol 102 ◽  
pp. 79-81
Author(s):  
A. Goldberg ◽  
S.D. Bloom
Keyword(s):  
Monte Carlo ◽  
State Vector ◽  
Basis Vector ◽  
Collective State ◽  
Dispersion Characteristics ◽  
Dipole Strength ◽  
The Third ◽  
Monte Carlo Algorithms ◽  
Third Moment ◽  
Very High

AbstractClosed expressions for the first, second, and (in some cases) the third moment of atomic transition arrays now exist. Recently a method has been developed for getting to very high moments (up to the 12th and beyond) in cases where a “collective” state-vector (i.e. a state-vector containing the entire electric dipole strength) can be created from each eigenstate in the parent configuration. Both of these approaches give exact results. Herein we describe astatistical(or Monte Carlo) approach which requires onlyonerepresentative state-vector |RV> for the entire parent manifold to get estimates of transition moments of high order. The representation is achieved through the random amplitudes associated with each basis vector making up |RV>. This also gives rise to the dispersion characterizing the method, which has been applied to a system (in the M shell) with≈250,000 lines where we have calculated up to the 5th moment. It turns out that the dispersion in the moments decreases with the size of the manifold, making its application to very big systems statistically advantageous. A discussion of the method and these dispersion characteristics will be presented.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

Off-axis electron holography applied to the study of interfaces

1992 ◽  
Vol 50 (1) ◽  
pp. 244-245
Author(s):  
J.K. Weiss ◽  
M. Gajdardziska-Josifovska ◽  
M. R. McCartney ◽  
David J. Smith
Keyword(s):  
Electric Fields ◽  
Resolution Enhancement ◽  
Interfacial Structure ◽  
Atomic Scale ◽  
Bulk Property ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Composition And Structure ◽  
Chemical Segregation ◽  
Diffraction Effects

Interfacial structure is a controlling parameter in the behavior of many materials. Electron microscopy methods are widely used for characterizing such features as interface abruptness and chemical segregation at interfaces. The problem for high resolution microscopy is to establish optimum imaging conditions for extracting this information. We have found that off-axis electron holography can provide useful information for the study of interfaces that is not easily obtained by other techniques.Electron holography permits the recovery of both the amplitude and the phase of the image wave. Recent studies have applied the information obtained from electron holograms to characterizing magnetic and electric fields in materials and also to atomic-scale resolution enhancement. The phase of an electron wave passing through a specimen is shifted by an amount which is proportional to the product of the specimen thickness and the projected electrostatic potential (ignoring magnetic fields and diffraction effects). If atomic-scale variations are ignored, the potential in the specimen is described by the mean inner potential, a bulk property sensitive to both composition and structure. For the study of interfaces, the specimen thickness is assumed to be approximately constant across the interface, so that the phase of the image wave will give a picture of mean inner potential across the interface.

A TEM study of the interface between organic matrix and aragonite in a biological hard tissue, nacre

1992 ◽  
Vol 50 (2) ◽  
pp. 1024-1025
Author(s):  
Jun Liu ◽  
Katie E. Gunnison ◽  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Mechanical Properties ◽  
Ion Beam ◽  
Laminated Composite ◽  
Organic Matrix ◽  
Pearl Oyster ◽  
Interfacial Structure ◽  
Interfacial Region ◽  
Thin Sections ◽  
Organic Layers ◽  
Transmission Electron

The interfacial structure between the organic and inorganic phases in biological hard tissues plays an important role in controlling the growth and the mechanical properties of these materials. The objective of this work was to investigate these interfaces in nacre by transmission electron microscopy. The nacreous section of several different seashells -- abalone, pearl oyster, and nautilus -- were studied. Nacre is a laminated composite material consisting of CaCO3 platelets (constituting > 90 vol.% of the overall composite) separated by a thin organic matrix. Nacre is of interest to biomimetics because of its highly ordered structure and a good combination of mechanical properties. In this study, electron transparent thin sections were prepared by a low-temperature ion-beam milling procedure and by ultramicrotomy. To reveal structures in the organic layers as well as in the interfacial region, samples were further subjected to chemical fixation and labeling, or chemical etching. All experiments were performed with a Philips 430T TEM/STEM at 300 keV with a liquid Nitrogen sample holder.

The use of charging effects in Al/Al2O3 metal matrix composite materials as contrast mechanism in the SEM

1990 ◽  
Vol 48 (4) ◽  
pp. 422-423
Author(s):  
Andreas M. Borchert
Keyword(s):  
Secondary Electron ◽  
Aluminum Matrix ◽  
Interfacial Structure ◽  
Resolving Power ◽  
Coated Sample ◽  
Material Combination ◽  
Uncoated Sample ◽  
Backscattered Electrons ◽  
Contrast Mechanism ◽  
Good Contrast

In Al/Al2O3 MMC's the metal/ceramic interfacial structure is of great concern because aluminum does not wet (i.e. bond) well to alumina. One proposed method to overcome this problem is to form a magnesium-rich spinel (MgAl2O4) as an additional phase between the aluminum matrix and the alumina particle. The spinel forms by diffusion of Mg from the matrix and improves the bonding. Typically the SEM would be the most suitable instrument to study the spinel, but this particular material combination (alumina/spinel) does not have sufficient secondary or backscattered electron contrast to allow for normal imaging. The purpose of this work was to develop a technique for examining the growth and morphology of this spinel at the Al/Al2O3 interface. Samples of an Al/Al2O3 MMC with a spinel at the particle interface were prepared according to standard metallographic procedures. Certain samples were sputter coated with a gold film of approximately 12 nm thickness; other samples were examined uncoated. Nonconductive, uncoated specimens charge under the incident electron beam if the accelerating voltage is below E1 or above E2 in Figure 1. In both of cases (below E1 and above E2) the number of electrons entering the sample is higher than the number of electrons leaving the sample. The resolving power of the SEM is usually degraded by this effect and therefore nonconductive specimens are coated with a layer of conductive material prior to observation. Figure 2 shows how this effect can create contrast between two materials due to its effect on the secondary electron detector bias voltage. Figure 3 shows that this contrast mechanism exists for the material combination alumina/spinel. The secondary electron image of a coated sample (3a) shows almost no contrast between alumina and spinel whereas the uncoated sample (3b) shows good contrast due to the different charging characteristics of the materials. The alumina charges stronger than the spinel and appears brighter in the image. The assumption that the effect is due to secondary electrons is supported by Figure 4. The micrograph in Figure 4a was obtained by backscattered electrons only and shows poor contrast whereas the micrograph in Figure 4b was obtained by secondary and backscattered electrons and shows good contrast. Figure 5 shows micrographs obtained at different operating voltages. The reduction in contrast at lower operating voltages is due to reduced charging.

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