scholarly journals Prediction of relative globularization rates in α + β titanium alloys as a function of initial crystal orientation

2020 ◽  
Vol 35 (8) ◽  
pp. 1113-1120
Author(s):  
Benjamin A. Begley ◽  
Keith Markham ◽  
Michael Mizak ◽  
Adam L. Pilchak ◽  
Victoria M. Miller
Keyword(s):  
Titanium Alloys ◽  
Crystal Orientation ◽  
Initial Crystal

Abstract

Microband-To-Microshear Band Transition near Grain Boundaries in BCC Steel

2007 ◽  
Vol 558-559 ◽  
pp. 873-878 ◽  
Author(s):  
Dorothée Dorner ◽  
Yoshitaka Adachi ◽  
Kaneaki Tsuzaki
Keyword(s):  
Grain Boundary ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Early Stage ◽  
Compression Tests ◽  
Grain Boundary Characteristics ◽  
Band Transition ◽  
Boundary Characteristics ◽  
Backscatter Diffraction ◽  
Initial Crystal

Compression tests were performed on Fe-3%Si specimens with few grains. The deformation microstructure and microtexture were investigated by electron backscatter diffraction (EBSD) and related to the initial crystal orientation and grain boundary characteristics. Groups of microbands were found that are characterised by a periodic change in crystal orientation, shear at the grain boundary, and the formation of new grains. It is supposed that these microband groups represent an early stage of microshear band development.

scholarly journals Influence of Initial Crystal Orientation and Carbon Content on Rolling Texture in 3 mass % Si steel

2021 ◽  
Vol 107 (5) ◽  
pp. 367-374
Author(s):  
Yukihiro Shingaki ◽  
Minoru Takashima ◽  
Yasuyuki Hayakawa
Keyword(s):  
Carbon Content ◽  
Crystal Orientation ◽  
Rolling Texture ◽  
Initial Crystal

Cube{100}<001> Grains Nucleation during Annealing of S-Oriented Aluminum Single Crystal

2018 ◽  
Vol 941 ◽  
pp. 1511-1516
Author(s):  
Magdalena M. Miszczyk ◽  
Henryk Paul
Keyword(s):  
Single Crystal ◽  
Crystal Lattice ◽  
Crystal Orientation ◽  
Small Deviation ◽  
Primary Recrystallization ◽  
High Angle Boundary ◽  
High Angle ◽  
Local Orientation ◽  
Aluminum Single Crystal ◽  
Initial Crystal

The crystallographic aspects of nucleation of cube grains during annealing have been analyzed in (234)[20-28 11] - oriented aluminum single crystal. The samples were plane strain compressed in a channel-die up to logarithmic strains of 0.5 (40%) and then annealed to develop initial and final stages of primary recrystallization. The deformed and annealed samples were analyzed using scanning electron microscopy equipped with EBSD facility. Local orientation measurements reveled that significant part of the sample deforms homogeneously with only small deviation from the initial crystal orientation. The heterogeneities were thin bands of localized strain in which the crystal lattice rotate towards another variant of S orientation. After annealing the orientations identified inside deformed/recovered areas were similar to that observed in the sample just after deformation. The crystal lattice of recrystallized grains exhibit a well-defined clockwise and anticlockwise rotations around the axes grouped near all normals of the {111} planes of the deformed/recovered state. The cube grains were observed in both homogeneously and heterogeneously deformed areas despite the cube-oriented nuclei surrounded by high angle boundary were not present in the as-deformed structure.

Direct Observation of the Diffusionless β → β + ω Transformation in Titanium Alloys

1971 ◽  
Vol 29 ◽  
pp. 122-123
Author(s):  
N. E. Paton ◽  
D. de Fontaine ◽  
J. C. Williams
Keyword(s):  
Electron Microscope ◽  
Titanium Alloys ◽  
Direct Observation ◽  
Dark Field ◽  
X Ray Diffraction ◽  
Resistivity Measurements ◽  
Selected Area Electron Diffraction ◽  
Ti Alloys ◽  
Thin Foils ◽  
Field Device

The electron microscope has been used to study the diffusionless β → β + ω transformation occurring in certain titanium alloys at low temperatures. Evidence for such a transformation was obtained by Cometto et al by means of x-ray diffraction and resistivity measurements on a Ti-Nb alloy. The present work shows that this type of transformation can occur in several Ti alloys of suitable composition, and some of the details of the transformation are elucidated by means of direct observation in the electron microscope.Thin foils were examined in a Philips EM-300 electron microscope equipped with a uniaxial tilt, liquid nitrogen cooled, cold stage and a high resolution dark field device. Selected area electron diffraction was used to identify the phases present and the ω-phase was imaged in dark field by using a (101)ω reflection. Alloys were water quenched from 950°C, thinned, and mounted between copper grids to minimize temperature gradients in the foil.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

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