Nanoscale Sn Inclusions in Al – Structure and Melting-Solidification Properties

1999 ◽  
Vol 580 ◽  
Author(s):  
E. Johnson ◽  
C.R.H. Bahl ◽  
V.S. Touboltsev ◽  
A. Johansen
Keyword(s):  
Size Dependence ◽  
Rutherford Backscattering Spectrometry ◽  
Lattice Parameters ◽  
Orientation Relationships ◽  
Size Dependent ◽  
Transmission Electron ◽  
The Matrix ◽  
Al Matrix ◽  
Melting And Solidification

AbstractAl-Sn surface alloys with 2-3 at.% Sn have been made by ion implantation of Sn in Al. The microstructure of the alloys consists of dense distributions of nanoscale Sn inclusions embedded in the Al matrix. For implantations carried out at 425 K the inclusions have sizes in the range from about 2 to 15 nm. The structure of the inclusions is tetragonal - the white Sn structure – with lattice parameters of a = 0.583 nm and c = 0.318 nm respectively, i.e. identical to the lattice parameters of bulk Sn. The inclusions grow in preferred alignment with the matrix and the most commonly observed orientation relationships is given by (100)Sn ||(111)Al and [010]Sn || [211]Al. The shape of the inclusions is partly faceted and partly rounded with larger flat facets on the {100}Sn/{111}Al interfaces. Melting and solidification of the inclusions, which have been studied by in-situ transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS) in combination with channeling, shows a distinct hysteresis. Melting of the inclusions which is associated with a distinct premelting, takes place in the range from about 430 K to 485 K, i.e. significantly below the bulk melting point of 505 K. The premelting is size dependent and the smallest inclusions melt at the lowest temperatures. Solidification requires a substantial undercooling and takes place from around 400 K with a much weaker size dependence.

Melting And Solidification Behaviour Of Lead Particles Embedded In Quasicrystalline Matrices

1998 ◽  
Vol 553 ◽  
Author(s):  
Alok Singh ◽  
A. P. Tsai
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Matrix Interface ◽  
Orientation Relationships ◽  
Scanning Calorimetry ◽  
Decagonal Phase ◽  
Solidification Behaviour ◽  
Transmission Electron ◽  
The Matrix ◽  
Melting And Solidification

AbstractComposites of nanoparticles of lead were prepared by embedding into Al-Cu-V and Al- Cu-Fe icosahedral, and Al-Cu-Co decagonal phase alloys by means of rapid solidification. The microstructure of these composites, the orientation relationships and the interfaces formed between the particles and the matrix has been studied by transmission electron microscopy. The melting and solidification behaviour of the lead particles in these matrices has been studied by differential scanning calorimetry. The microstructure and the nature of the particle-matrix interface has been related to the melting/solidification behaviour of the particles in the matrix.

Quasicrystals in a rapidly solidified AlMnCrSi alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 184-185
Author(s):  
Y.X. Guo ◽  
S. Andersen ◽  
R. Høier
Keyword(s):  
Reciprocal Lattice ◽  
Icosahedral Quasicrystal ◽  
Bright Field Image ◽  
Orientation Relationships ◽  
Transmission Electron ◽  
Dislocation Models ◽  
The Matrix ◽  
The One ◽  
Rapidly Solidified ◽  
Al Matrix

Since the icosahedral quasicrystal (IQ) was first reported and described, transmission electron microscopy (TEM) has played an important role in structural studies of the material. Several types of IQ structural models have been reported, but the detailed structure is still not solved. In addition the quasicrystals are frequently strained and dislocation models have been suggested. The present investigation is focused on these latter aspects through TEM-studies of interface boundaries and defects in a rapidly solidified Al-Mn-Cr-Si alloy.The bright field image in Fig. 1 shows IQ precipitates in an Al-matrix. The particles have two different orientation relationships with the matrix. These relationships have been found through detailed determination of the reciprocal lattice for several particle/matrix combinations. The diffraction pattern in Fig. 2a shows a <100> Al zone. Here three orthogonal 2-fold axes in the quasicrystal are along the three 4-fold aluminium axes. In Fig. 2b one of the three orthogonal 2- fold axes is along a cube direction and the two others along two orthogonal <110> axes in the facecentered Al matrix. The first relationship corresponds to the one observed previously for much smaller icosahedral particles.

scholarly journals The Evolution of Complex Carbide Precipitates in a Low Alloy Cr–Mo–V Steel after Long-Term Aging Treatment

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1724 ◽  
Author(s):  
Zili Liu ◽  
Chunming Liu ◽  
Lede Miao ◽  
Xiaofei Guo ◽  
Jianhua Ding ◽  
...  
Keyword(s):  
Aging Treatment ◽  
Nucleation Site ◽  
Secondary Phases ◽  
Orientation Relationships ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Complex Carbide

Complex carbide precipitates in a quenched and tempered low alloy Cr–Mo–V steel after long-term aging at 650 °C for 13,000 h and 30,000 h were investigated in this study. The mass fraction and sizes of precipitates were quantified by electrolytical extraction technique. The types of precipitate were further studied by combined X-ray diffraction and transmission electron microscopy with selected area electron diffraction and energy dispersive spectrometry. A series of carbide precipitates, namely MC, M7C3, M6C, and M2C, were found existing in the near-equilibrium state. The precipitate sequence of these carbides was identified as MC + M7C3 + M2C → MC + M2C + M7C3 + M6C → MC + M7C3 + M6C. It was clarified that the stable phases for the investigated steel aged at 650 °C were composed of MC, M7C3, and M6C. For the first time, the in-situ transformations of M2C to M6C and M7C3 to M6C were directly observed. It was also observed that the nucleation site of the M6C was located at the interface of M7C3 carbides and the matrix. The orientation relationships between the secondary phases of the in-situ transforming carbides aged for 13,000 h and 30,000 h at 650 °C were established. The coherent interfaces between these secondary phases became incoherent with prolonged aging treatment due to the exerted strain field of the growing carbides.

In situ TEM observations of melting in nanosized eutectic Pb-Cd inclusions embedded in Al

1996 ◽  
Vol 54 ◽  
pp. 986-987
Author(s):  
S. Hagège ◽  
U. Dahmen ◽  
E. Johnson ◽  
A. Johansen ◽  
V.S. Tuboltsev
Keyword(s):  
Electron Microscope ◽  
Melt Spinning ◽  
Ternary Alloys ◽  
Solid Matrix ◽  
Eutectic System ◽  
In Situ Tem ◽  
In Situ Observation ◽  
Orientation Relationships ◽  
Transmission Electron

Small particles of a low-melting phase embedded in a solid matrix with a higher melting point offer the possibility of studying the mechanisms of melting and solidification directly by in-situ observation in a transmission electron microscope. Previous studies of Pb, Cd and other low-melting inclusions embedded in an Al matrix have shown well-defined orientation relationships, strongly faceted shapes, and an unusual size-dependent superheating before melting.[e.g. 1,2].In the present study we have examined the shapes and thermal behavior of eutectic Pb-Cd inclusions in Al. Pb and Cd form a simple eutectic system with each other, but both elements are insoluble in solid Al. Ternary alloys of Al (Pb,Cd) were prepared from high purity elements by melt spinning or by sequential ion implantation of the two alloying additions to achieve a total alloying addition of up to lat%. TEM observations were made using a heating stage in a 200kV electron microscope equipped with a video system for recording dynamic behavior.

The orientation relationships of nanobelt-like Si2Hf precipitates in an Al–Si–Mg–Hf alloy

2016 ◽  
Vol 49 (4) ◽  
pp. 1223-1230 ◽  
Author(s):  
Xueli Wang ◽  
Huilan Huang ◽  
Xinfu Gu ◽  
Yanjun Li ◽  
Zhihong Jia ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Coincident Site Lattice ◽  
Orthorhombic Structure ◽  
Orientation Relationships ◽  
Lattice Distribution ◽  
Site Lattice ◽  
Transmission Electron ◽  
Habit Planes ◽  
Al Matrix

The orientation relationships (ORs) between the Al matrix and Si2Hf precipitates with an orthorhombic structure in an Al–Si–Mg–Hf alloy after heat treatment at 833 K for 20 h were investigated by transmission electron microscopy and electron diffraction. Four ORs are identified as (100)Al||(010)p, (0\overline {1}1)Al||(101)pand [011]Al||[\overline {1}01]p; (11\overline {1})Al||(010)pand [011]Al||[\overline {1}01]p; (12\overline {1})Al||(010)p, (101)Al||(100)pand [1\overline {11}]Al||[001]p; (\overline {11}1)Al||(010)pand [112]Al||[\overline {1}01]p. The habit planes of these four ORs are rationalized by the fraction of good atomic matching sites at the interface. In addition, the formation of Si2Hf precipitates with a nanobelt-like morphology is interpreted on the basis of the near-coincident site lattice distribution.

Investigation of Pt Bottom Electrodes for "In-Situ" Deposited Pb(Zr,Ti)O3 (PZT) thin Films

1991 ◽  
Vol 243 ◽  
Author(s):  
Rainer Bruchhaus ◽  
Dana Pitzer ◽  
Oliver Eibl ◽  
Uwe Scheithauer ◽  
Wolfgang Hoesler
Keyword(s):  
Elevated Temperatures ◽  
Diffusion Processes ◽  
Rutherford Backscattering Spectrometry ◽  
Layer Sequence ◽  
Si Substrates ◽  
Transmission Electron ◽  
In Situ Deposition ◽  
Electron Spectrometry ◽  
Heating Up

AbstractThe deposition of the bottom electrode plays a key role in the fabrication of ferroelectric capacitors. Processing at elevated temperatures of up to 800°C can give rise to diffusion processes and thereof formation of harmful dielectric layers.In this paper we used Rutherford backscattering spectrometry (RBS), Auger electron spectrometry (AES) and transmission electron microscopy (TEM) to study Pt/Ti/SiO2/Si substrates with various thicknesses of the Ti and Pt layers. During heating up to about 450°C in vacuum the initial layer sequence remains unchanged. However, drastic changes occur when the electrodes are exposed to Ar/O2 atmosphere during heat treatment. Oxidation induced diffusion of Ti into Pt and oxidation of Ti were observed. A Pt electrode with a 100 nm thick Ti adhesion layer proved to be suitable for the "in-situ" deposition of PZT films.

Size dependent behavior of Fe3O4crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

2017 ◽  
Vol 19 (31) ◽  
pp. 20867-20880 ◽  
Author(s):  
David C. Bock ◽  
Christopher J. Pelliccione ◽  
Wei Zhang ◽  
Janis Timoshenko ◽  
K. W. Knehr ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Transmission Electron ◽  
Dependent Behavior ◽  
X Ray Absorption

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.

scholarly journals High-Resolution Microstructure Characterization of Additively Manufactured X5CrNiCuNb17-4 Maraging Steel during Ex and in Situ Thermal Treatment

2021 ◽  
Author(s):  
Mihaela Albu ◽  
Bernd Panzirsch ◽  
Hartmuth Schröttner ◽  
Stefan Mitsche ◽  
Klaus Reichmann ◽  
...  
Keyword(s):  
Maraging Steel ◽  
Elevated Temperatures ◽  
Scanning Transmission Electron Microscope ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Matrix ◽  
Powder Particles ◽  
In Situ Heating ◽  
Heating Up

Powder and SLM additively manufactured parts of X5CrNiCuNb17-4 maraging steel were systematically investigated by electron microscopy to understand the relationship between the properties of the powder grains and the microstructure of the printed parts. We prove that satellites, irregularities and superficial oxidation of powder particles can be transformed into an advantage through the formation of nanoscale (AlMnSiTiCr)-oxides in the matrix during the printing process. The nano-oxides showed extensive stability in terms of size, spherical morphology, chemical composition and crystallographic disorder upon in situ heating up to 950&deg;C in the scanning transmission electron microscope. Their presence thus indicates a potential for oxide-dispersive strengthening of this steel, which may be beneficial for creep resistance at elevated temperatures. The nucleation of copper clusters and their evolution into nanoparticles as well as the precipitation of Ni and Cr particles upon in situ heating have as well been systematically documented.

In situ transmission electron microscope measurements of solid Al-solid Pb and solid Al-liquid Pb surface-energy anisotropy in rapidly solidified Al-5% Pb (by mass)

1987 ◽  
Vol 414 (1847) ◽  
pp. 499-507 ◽  
Keyword(s):  
Electron Microscope ◽  
Melting Point ◽  
Surface Energy ◽  
Transmission Electron Microscope ◽  
Room Temperature ◽  
Transmission Electron ◽  
Increasing Temperature ◽  
Rapidly Solidified ◽  
Al Matrix

Alloys of Al-5% Pb and Al-5% Pb-0.5% Si (by mass) have been manufactured by rapid solidification and then examined by transmission electron microscopy. The rapidly solidified alloy microstructures consist of 5-60 nm Pb particles embedded in an Al matrix. The Pb particles have a cube-cube orientation relation with the Al matrix, and are cub-octahedral in shape, bounded by {100} Al, Pb and {111} Al, Pb facets. The equilibrium Pb particle shape and therefore the anisotropy of solid Al-solid Pb and solid Al-liquid Pb surface energies have been monitored by in situ heating in the transmission electron microscope over the temperature range between room temperature and 550°C. The ani­sotropy of solid Al-solid Pb surface energy is constant between room temperature and the Pb melting point, with a {100} Al, Pb surface energy about 14% greater than the {111} Al, Pb surface energy, in good agreement with geometric near-neighbour bond energy calculations. The {100} AI, Pb facet disappears when the Pb particles melt, and the anisotropy of solid Al-liquid Pb surface energy decreases gradually with increasing temperature above the Pb melting point, until the Pb particles become spherical at about 550°C.

Microstructural Characterization, Mechanical Properties and Wear Resistance of TiCP Reinforced Ni-Alloy Coatings by Laser Synthesis

2000 ◽  
Author(s):  
D. L. Tu ◽  
A. Kar ◽  
X. L. Wu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Wear Resistance ◽  
Chemical Reaction ◽  
Phase Interface ◽  
High Fracture Toughness ◽  
Transmission Electron ◽  
Ni Alloy ◽  
The Matrix

Abstract Titanium carbide particle (TiCp)-reinforced Ni alloy composite coatings are synthesized by laser cladding using a cw 3 kW CO2 laser. Two kinds of coatings are possible in terms of the origin of TiCp: undissolved TiCp and in-situ generated TiCp. The former originates from the TiCp pre-coated on the sample whereas the latter from in-situ chemical reaction between titanium and graphite in the molten pool during laser irradiation. For the coating reinforced by TiCp formed in-situ, the sub-micron TiCp particles are formed and uniformly distributed because of the in-situ reaction and trapping effect during rapid solidification. Graded distribution of TiCp is obtained on a macro scale. The volume fraction increases from 1.86% at the coating-substrate interface to 38.4% at the coating surface. For the coating reinforced by undissolved TiCp, analytical transmission electron microscopy (ATEM) and high resolution transmission electron microscopy (HRTEM) observations show the existence of the epitaxial growth of TiC, the precipitation of CrB and M23C6, and the chemical reaction between Ti and B elements around phase interfaces of undissolved TiCp. In the matrix near the phase interface of undissolved TiCp, the loading curve obtained by nanoindenter exhibits pop-in phenomena due to the plastic deformation of cracks or debonding of TiCp from the matrix. For TiCp generated in-situ, no pop-in mark appears, indicating high fracture toughness. Coating with TiCp generated in-situ exhibits higher hardness and modulus than the coating with undissolved TiCp at regions near the phase interface. The coating reinforced by TiCp generated in-situ also displays higher impact wear resistance and abrasive wear resistance compared to the coatings with undissolved TiCp and without TiCp respectively.

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