Morphology and thermal characteristics of nano-sized Pb–Sn inclusions in Al

2002 ◽  
Vol 17 (11) ◽  
pp. 2875-2883 ◽  
Author(s):  
P. Bhattacharya ◽  
V. Bhattacharya ◽  
K. Chattopadhyay
Keyword(s):  
Orientation Relationship ◽  
Eutectic Temperature ◽  
Thermal Characteristics ◽  
Face Centered Cubic ◽  
Orientation Relation ◽  
Scanning Calorimetry ◽  
Cube Orientation ◽  
The Matrix ◽  
Face Centered ◽  
Two Phases

Nanoembedded aluminum alloys with bimetallic dispersoids of Sn and Pb of compositions Sn82–Pb18, Sn64–Pb36, and Sn54–Pb46were synthesized by rapid solidification. The two phases, face-centered-cubic Pb and tetragonal Sn solid-solution, coexist in all the particles. The crystallographic relation between the two phases and the matrix depends upon the solidification pathways adopted by the particles. For Al–(Sn82–Pb18), we report a new orientation relation given by [011]Al//[010]Sn and (o11)A1//(101)Sn. Pb exhibits a cube-on-cube orientation with Al in few particles, while in others no orientation relationship could be observed. In contrast, Pb in Sn64–Pb36and Sn54–Pb46particles always exhibits cube-on-cube orientation with the matrix. Sn does not show any orientation relationship with Al or Pb in these cases. Differential scanning calorimetry studies revealed melting at eutectic temperature for all compositions, although solidification pathways are different. Attempts were made to correlate these with the melting and heterogeneous nucleation characteristics.

scholarly journals Effects of C Addition on the Microstructures of As-Cast Cu–Fe–P Alloys

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2772 ◽  
Author(s):  
Chen ◽  
Hu ◽  
Guo ◽  
Zou ◽  
Liu ◽  
...  
Keyword(s):  
Orientation Relationship ◽  
Supersaturated Solid Solution ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Matrix Microstructure ◽  
The Matrix ◽  
Bcc Structure ◽  
The Difference ◽  
Face Centered ◽  
Fcc Structure

Effects of C addition on the microstructures of as-cast Cu–Fe–P (mass fraction) alloys were systematically investigated. The results show that C addition can refine the matrix microstructure and make Fe particles finer. The Fe particles observed in both the non-C-alloyed and C-alloyed specimens are α-Fe particles, which possess a body-centered cubic (bcc) structure with a Nishiyama–Wassermann orientation relationship with the matrix. C is reported to be an γ-Fe stabilizer in the literature. The reason for the difference between the phases of Fe particles observed in this study, and that reported in the literature, are finally discussed. Additionally, C addition facilitates the decomposition of the supersaturated solid solution which occurs by the simultaneous precipitation of very fine Fe particles. Such initial decomposition product has an face-centered cubic (fcc) structure with a cube-on-cube orientation relationship with the matrix.

Interface structure of face-centered-cubic-Ti thin film grown on 6H–SiC substrate

2000 ◽  
Vol 15 (10) ◽  
pp. 2121-2124 ◽  
Author(s):  
Y. Sugawara ◽  
N. Shibata ◽  
S. Hara ◽  
Y. Ikuhara
Keyword(s):  
Thin Film ◽  
Orientation Relationship ◽  
High Resolution Electron Microscopy ◽  
Electron Beam Evaporation ◽  
Face Centered Cubic ◽  
High Adhesion ◽  
Resolution Electron ◽  
Face Centered ◽  
Relationship Of ◽  
High Degree

A titanium thin film was deposited on the flat (0001) face of a 6H–SiC by electron beam evaporation at room temperature in a vacuum of 5.1 × 10−8 Pa. The Ti film was epitaxially grown on the surface, and the interface between Ti and SiC was characterized by high-resolution electron microscopy. It was found that the structure of the deposited titanium is face-centered cubic (fcc), although bulk titanium metal usually has a hexagonal close-packed or body-centered cubic crystal structure. We believe that the unusual fcc structure of Ti thin film is due to the high adhesion of the film to the substrate and the high degree of coherency between them. The orientation relationship of the fcc-Ti/6H–SiC interface was (111)fcc-Ti//(0001)6H–SiC and [110]fcc-Ti//[1120]6H−SiC. Preliminary calculations indicate that this orientation relationship maximizes the lattice coherency across the interface.

scholarly journals Multi-Length Scale Characterization of the Gibeon Meteorite using Electron Backscatter Diffraction

2007 ◽  
Vol 15 (5) ◽  
pp. 6-11 ◽  
Author(s):  
Matthew M. Nowell ◽  
John O. Carpenter
Keyword(s):  
Electron Backscatter Diffraction ◽  
Nickel Content ◽  
Iron Core ◽  
Face Centered Cubic ◽  
Iron Nickel ◽  
Scale Characterization ◽  
Face Centered ◽  
Two Phases ◽  
Backscatter Diffraction

The Gibeon meteorite is a differentiated iron meteorite that fell in Nambia, Africa in prehistoric times, with fragments spread over an area 70 miles wide and 230 miles long. The Gibeon fall was initially discovered in 1836, and hundreds of thousands of kilograms of fragments have been recovered. These fragments represent the iron core of a meteorite that cooled and crystallized over thousands of years (Norton 2002).The microstructure of the Gibeon meteorite, which is primarily an iron-nickel alloy, consists of two phases: kamacite, a body-centered cubic material and taenite, a face-centered cubic material that metallurgists would refer to as ferrite and austenite respectively. This material initially crystallizes as taenite, and as the temperature decreases, transforms into kamacite. This meteorite is classified as a Fine Octahedrite (Of) with an average Nickel content of approximately 7.9%

One Pot, Two Phases: Individual Orthorhombic and Face-Centered Cubic ZnSnO3 Obtained Synchronously in One Solution

2014 ◽  
Vol 53 (23) ◽  
pp. 12289-12296 ◽  
Author(s):  
Ying Wang ◽  
Peng Gao ◽  
Di Bao ◽  
Longqiang Wang ◽  
Yujin Chen ◽  
...  
Keyword(s):  
Face Centered Cubic ◽  
One Pot ◽  
Face Centered ◽  
Two Phases

A symmetry-violating precipitation process induced under irradiation

1990 ◽  
Vol 48 (4) ◽  
pp. 930-931
Author(s):  
W. Kesternich
Keyword(s):  
Orientation Relationship ◽  
Neutron Irradiation ◽  
Dark Field ◽  
Fast Neutrons ◽  
Double Diffraction ◽  
Cube Orientation ◽  
Precipitate Growth ◽  
The Matrix ◽  
The Common ◽  
Diffraction Effects

TiC precipitates in austenitic steel have been found to reveal a very unusual precipitation behaviour /l,2/. As a consequence, nucleation initiated by dislocation recovery or growth induced during recrystallization can be used to create predesired modifications of the microstructure and the mechanical properties /2—3/. The extraordinary high resistance to precipitate growth and coarsening /l/ appears to be the key property in these applications and also appears to be the origin for a unique precipitate phenomenon which was observed in the present irradiation experiment.A 1.4970 type steel (15Ni—15Cr austenite, containing Ti and C) was neutron irradiated at 845 K to a dose of 2.6 x 1025 m-2 thermal neutrons (helium production) and 3.0 x 1025 fast neutrons (1.5dpa). Before irradiation the steel was solution annealed leaving about half of the Ti and C in supersaturated solution. Defect cascades introduced by the neutron irradiation acted as nucleation centres for MC (M=Ti, Nb, Mo...) precipitates as has already previously been demonstrated in Ti- and Nb-stabilized steels /4/. In addition to the common, irregularly shaped MC precipitates, however, two further precipitate variants were created during the present high temperature neutron irradiation. One precipitate variant was star—shaped with cube—on—cube orientation relationship with the matrix. The other variant was nail—shaped. Analysis of crystal structure and orientation relationship of the nail—shaped precipitates was made difficult by their small shape and by double diffraction effects. Fig. la shows a (001) SAD pattern of matrix (heavy spots) and precipitates (fine spots). The quadruplets in the vicinity of <110> are created from the new precipitates. Each of the four quadruplet spots actually consists of three closely spaced spots (Fig. lb), and the eight precipitate spots surrounding each of the matrix spots in Fig. la each consist of two spots. After the double diffraction effects had been assigned (schematic in Fig. lb for example) they were reduced by specified specimen tilting around two axes (Fig. lc). It was found by combined dark- field and diffraction analyses that all diffraction spots originated from TiC precipitates and that four orientation variants of the TiC precipitates were distinguishable. They are imaged in Fig. 1d in bright field and in Fig. 2 in four corresponding dark field images by using reflections 0 to 3 of Fig. lc. 0 shows precipitates of the common cube—on— cube orientation relationship. 1 to 3 shows nail—shaped precipitates with nail axes pointing along the three <110> directions. The diffraction analysis revealed that the lattice of the nail precipitates is rotated by 45 degrees around the nail axes from cube-on-cube orientation, thus giving rise to the three orientation variants.

Microstructure and Mechanical Properties of the W-Ni-Co System Refractory High-Entropy Alloys

2015 ◽  
Vol 816 ◽  
pp. 324-329 ◽  
Author(s):  
Hui Jiang ◽  
Li Jiang ◽  
Yi Ping Lu ◽  
Tong Min Wang ◽  
Zhi Qiang Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Melting Temperatures ◽  
Arc Melting ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Face Centered

The elements Mo, Cr and V were added to the W-Ni-Co system high entropy alloys, the effects of these added elements on microstructure and mechanical properties of these alloys were studied. The alloys were produced by vacuum arc melting. The compositions were W0.5Ni2Co2VMo0.5,W0.5Ni2Co2VCr0.5and W0.5Ni2Co2CrMo0.5(denoted as Alloy 1, Alloy 2 and Alloy 3) respectively. The theoretical melting temperatures were higher than 2000 K. X-ray diffraction, SEM and energy dispersive spectroscopy (EDS) results indicated that the matrix of the alloys is face-centered cubic (FCC) solid-solution, the alloys showed dendrite crystal structure. Ni, Co elements were enriched in the dendrite areas, the W, Mo were enriched in the inter-dendrite regions ,while V, Cr elements were uniform distribution. The Vickers hardness of these alloys was 376.1 HV, 255.88 HV and 306.8 HV, respectively. The yield strength values (σ0.2) of Alloy 1, Alloy 2 and Alloy 3 were approximately 1000MPa, 750MPa, 250MPa, respectively. The alloys show good compression plasticity deformation capacity at RT.

Characterization of an anomaly in the crystallographic orientation of plate-like carbides precipitated in a wrought Ni-base superalloy

2012 ◽  
Vol 45 (4) ◽  
pp. 719-725 ◽  
Author(s):  
H. W. Jeong ◽  
I. S. Kim ◽  
S. M. Seo ◽  
Y. S. Yoo ◽  
B. G. Choi ◽  
...  
Keyword(s):  
Orientation Relationship ◽  
Crystallographic Orientation ◽  
Boundary Energy ◽  
Coincidence Site Lattice ◽  
Elastic Strain Energy ◽  
Coincidence Site Lattice Boundary ◽  
Site Lattice ◽  
Cube Orientation ◽  
The Matrix ◽  
Lattice Boundary

Face-centred cubic Cr-rich carbide is known to precipitate in a face-centred cubic matrix with a cube–cube orientation relationship, thereby minimizing the elastic strain energy. In the present study, for the first time, the precipitation was observed of an abnormal Cr-rich carbide, which did not have the cube–cube orientation relationship in its face-centred cubic matrix. The abnormally oriented carbides nucleated and grew around random grain boundaries, and were observed to have a lamellar or plate-like morphology. The crystallographic orientation anomaly was characterized by measuring the tilt angles of the three crystal poles of the matrices, carbides and adjacent grains, using a transmission electron microscope to find the closest coincidence site lattice boundary. The carbides showed a slight deviation from a cube–cube orientation with adjacent grains and did not present any particular orientational relationship with the matrix. The deviation angles from coincidence site lattice boundaries between the matrices and carbides were smaller than those between matrices and adjacent grains. The abnormally oriented carbides appeared to nucleate on adjacent grains, and underwent a rotation within the matrix during the initial stage of growth to release the phase boundary energy between the carbides and the matrix.

Investigation on Structure Transition of Fullerene During Mechanical Alloying and Subsequent Treatments

2000 ◽  
Vol 15 (7) ◽  
pp. 1528-1537
Author(s):  
Z. G. Liu ◽  
H. Ohi ◽  
K. Masuyama ◽  
K. Tsuchiya ◽  
M. Umemoto
Keyword(s):  
Mechanical Milling ◽  
Polymerization Process ◽  
Molar Ratio ◽  
Face Centered Cubic ◽  
Scanning Calorimetry ◽  
Structure Transition ◽  
Characterization Methods ◽  
Fullerene Soot ◽  
The Face ◽  
Face Centered

Mechanical milling of fullerene (soot containing C60/C70 fullerenes in a 8:2 molar ratio) was investigated through various characterization methods. It was found that mechanical milling would not destroy the molecular structure of fullerene C60 (C70), while the long-range order of the face-centered-cubic crystalline structure was easily modified and transformed into amorphous phase, a mixture of fullerene C60 (C70) polymers and monomers. Differential scanning calorimetry analysis revealed a recovery of polymers to pristine fullerene molecules at 678 K, which is much higher than the reported depolymerization temperature of fullerene polymers induced by photo irradiation and by high-pressure–temperature processes. It is suggested that the contaminated Fe acts as a catalyst in the polymerization process.

Plasticity and Size Effects in High Purity Cobalt: An Experimental Study

2016 ◽  
Vol 879 ◽  
pp. 560-565
Author(s):  
Gwendoline Fleurier ◽  
Mayerling Martinez ◽  
Pierre Antoine Dubos ◽  
Eric Hug
Keyword(s):  
Size Effects ◽  
Threshold Value ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Tem Analysis ◽  
Cubic Metals ◽  
Hexagonal Close Packed ◽  
A Value ◽  
Face Centered ◽  
Two Phases

The occurrence of size effects in cobalt was examined by the analysis of mechanical properties of samples with thickness t, in a large range of grain size d giving a number of grains across the thickness t/d. On Hall-Petch plots, from the very beginning of plastic strain, two linear behaviors are notable: the polycrystalline one for higher t/d and the multicrystalline one for lower t/d in which the flow stress is strongly reduced. (t/d)c is the threshold value between the two behaviors taking a value of around 14. This high value is directly linked to the low stacking fault energy of cobalt. The microstructure of the polycrystalline samples exhibits a strong basal texture and a small proportion of a secondary face-centered cubic phase in a hexagonal close-packed main phase was evidenced. TEM analysis enables to characterize the dislocations and the stacking faults present in the two phases. To complete the analysis, two plasticity stages can be distinguished: stage A corresponding to dislocations gliding and stage B driven by twinning. Size effects in cobalt are found to occur during gliding process and could be related to surface effects as previously shown in face-centered cubic metals.

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