scholarly journals Anisotropy of Microstructure and Strength in Fiber Textured Molybdenum Alloys

1987 ◽  
Vol 7 (1) ◽  
pp. 1-10 ◽  
Author(s):  
T. Oyama ◽  
J. Wadsworth
Keyword(s):  
Grain Boundaries ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
Fiber Texture ◽  
Good Ductility ◽  
Fibre Texture ◽  
Brittle Behavior ◽  
Molybdenum Alloys

Molybdenum and molybdenum alloys exhibit brittle behavior in the transverse direction of wrought bar stock despite having good ductility in the longitudinal direction. This is believed to be due to the presence of cracked-carbide stringers on adversely oriented grain boundaries. In the present paper, the possible role of anisotropy in strength, as a result of the presence of a strong fiber texture, is investigated. It is concluded, both theoretically and experimentally, that anistropy in strength between the transverse and longitudinal direction of barstock containing a perfect fibre texture is not a factor promoting brittle behavior.

Room-temperature magnetoelectric coupling, dielectric and impedance studies of 0.5Zn0.3Ni0.7Fe2O4–0.5HoMnO3 nanocomposite

2018 ◽  
Vol 32 (19) ◽  
pp. 1840060 ◽  
Author(s):  
Rajesh Debnath ◽  
S. K. Mandal ◽  
A. Nath ◽  
P. Dey
Keyword(s):  
Magnetic Field ◽  
Dielectric Constant ◽  
Grain Boundaries ◽  
Applied Magnetic Field ◽  
Room Temperature ◽  
Transverse Direction ◽  
Dominant Role ◽  
Dc Magnetic Field ◽  
Nyquist Plots

We have investigated strain mediated magnetoelectric (ME) coupling and impedance properties in 0.5Zn[Formula: see text]Ni[Formula: see text]Fe2O4–0.5HoMnO3 nanocomposites at room-temperature. The ME voltage is measured in both longitudinal and transverse direction at a frequency of 173 Hz. The impedance, real and imaginary parts of impedance and dielectric constant have been carried out in presence of DC magnetic field. With the application of magnetic field, slight decrease in dielectric constant has been observed. The impedance, real and imaginary parts of impedance are found to increase with the increase in the applied magnetic field. Nyquist plots have been fitted using three parallel combinations of resistances–capacitance circuits. Fitted parameters show the dominant role of grain boundaries, grains and interface of two types of grains of the sample.

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

Carbide precipitation and chromium depletion on coherent twin boundaries in deformed 304 stainless steels

1992 ◽  
Vol 50 (2) ◽  
pp. 1216-1217
Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D.J. Matlock ◽  
W.W. Fisher ◽  
P.M. Tarin ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Stainless Steels ◽  
Interfacial Free Energy ◽  
Carbide Precipitation ◽  
Twin Boundaries ◽  
Invariant Structure ◽  
Heat Treated ◽  
Constant Structure ◽  
Cr Depletion

Coherent annealing-twin boundaries are constant structure and energy interfaces with an average interfacial free energy of ∼19mJ/m2 versus ∼210 and ∼835mJ/m2 for incoherent twins and “regular” grain boundaries respectively in 304 stainless steels (SS). Due to their low energy, coherent twins form carbides about a factor of 100 slower than grain boundaries, and limited work has also shown differences in Cr-depletion (sensitization) between twin versus grain boundaries. Plastic deformation, may, however, alter the kinetics and thermodynamics of twin-sensitization which is not well understood. The objective of this work was to understand the mechanisms of carbide precipitation and Cr-depletion on coherent twin boundaries in deformed SS. The research is directed toward using this invariant structure and energy interface to understand and model the role of interfacial characteristics on deformation-induced sensitization in SS. Carbides and Cr-depletion were examined on a 20%-strain, 0.051%C-304SS, heat treated to 625°C-4.5h, as described elsewhere.

AISI 1141

Alloy Digest ◽  
1983 ◽  
Vol 32 (3) ◽  
Keyword(s):  
Carbon Steel ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
Heat Treating ◽  
Automatic Machine ◽  
Steel Mills ◽  
Light Duty ◽  
High Production ◽  
Ball Joints ◽  
Machining Characteristics

Abstract AISI 1141 is a resulfurized carbon steel containing nominally 1.50% manganese and 0.08-0.13% sulfur to give it free-machining characteristics. It has relatively low hardenability. Its ductility and toughness are fairly good in the longitudinal direction but tend to be low in the transverse direction. It is highly recommended for high-production automatic-machine products. Among its many uses are screws, bolts, ball joints, spindles and light-duty gears. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-93. Producer or source: Carbon steel mills.

scholarly journals Internal melt figures in ice by rapid adiabatic compression

1994 ◽  
Vol 40 (134) ◽  
pp. 132-134
Author(s):  
R.E. Gagnon ◽  
C. Tulk ◽  
H. Kiefte
Keyword(s):  
Phase Transformations ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Adiabatic Compression ◽  
Air Bubbles ◽  
Water Ice ◽  
Deep Focus ◽  
And Behavior ◽  
First Time

AbstractSingle crystals and bicrystals of water ice have been adiabatically pressurized to produce, and clearly illustrate, two types of internal melt figures: (1) dendritic figures that grow from nucleation imperfections on the specimen’s surface, or from air bubbles at grain boundaries, into the ice as pressure is elevated; and (2) compression melt fractures, flat liquid-filled disks, that nucleate at imperfections in the crystal and grow with the application of pressure eventually to sprout dendritic fingers at the periphery. The transparency of the ice permitted visualization of the growth and behavior of the figures, and this could be an important tool in understanding the role of phase transformations in deep-focus earthquakes. Correlation between figure size and pressure is noted for the first time.

Quality Assessment of Weldable Steel Mark P355NH from Decompression Chamber Construction for Diving

2012 ◽  
Vol 217-219 ◽  
pp. 2381-2387
Author(s):  
Doru Romulus Pascu ◽  
Radu Alexandru Roşu ◽  
Iuliana Duma ◽  
Horia Daşcău
Keyword(s):  
Test Temperature ◽  
Transverse Direction ◽  
Mechanical Characteristics ◽  
Longitudinal Direction ◽  
Pressure Vessels ◽  
Fine Grained ◽  
Weldable Steel ◽  
Breaking Energy ◽  
Fine Grained Steels ◽  
Selection Of

Non-alloyed P355NH steel according to EN 10028-3:2003 belongs to a group of fine-grained steels for pressure vessels being used in welded construction at decompression chamber for divers. Values of the chemical, structural and mechanical characteristics and steel toughness experimentally determined fit the analyzed steel in P355NH steel group according to EN 10028-3:2003. The toughness of the analyzed steel at the test temperature of -30°C is characterized by high values of fracture energy KV in longitudinal direction between 48 and 86 J and on transverse direction between 17 and 34J. Steel toughness at the test temperature of -30°C required by ABS standard (in Section 4/5.3 and Table 1) provides for breaking energy KV of min. 35J, with ductile fracture surfaces, value that is not respected at some lots of the three batches (A, B, C) of steel. Finally, based on the direct correlation established between HV10 hardness of the fine structure and the toughness it was made a selection of the lots of non-alloy steel P355NH which correspond to ABS norm for welded construction of the decompression chamber for divers

scholarly journals Role of Grain Boundaries in diffusional Phenomena during Gas Nitriding of Pure Iron

2011 ◽  
Vol 10 ◽  
pp. 2943-2948 ◽  
Author(s):  
S. Fare ◽  
N. Lecis ◽  
E. Brescia ◽  
M. Mazzola
Keyword(s):  
Grain Boundaries ◽  
Pure Iron ◽  
Gas Nitriding

Electron Transport in Highly Textured Metal Films Grown by Partially Ionized Beam Deposition

1995 ◽  
Vol 403 ◽  
Author(s):  
S. R. Soss ◽  
B. Gittleman ◽  
K. E. Mello ◽  
T.-M. Lu ◽  
S. L. Lee
Keyword(s):  
Dislocation Density ◽  
Grain Boundaries ◽  
Electron Scattering ◽  
Delta Function ◽  
Fiber Texture ◽  
Cu Films ◽  
Film Resistivity ◽  
Average Dislocation Density ◽  
Amorphous Substrates ◽  
Partially Ionized

AbstractIn principle, the resistivity of bulk FCC cubic materials should not depend on the orientation due to the fact that the conductivity tensor is single valued. However, we show that this conclusion is not valid for thin films. Deposition of highly oriented Al, Ag, and Cu films on amorphous substrates using the partially ionized beam (PIB) technique exhibit a resistivity which is strongly correlated with the texture, i.e., the tighter the texture, the lower the film resistivity. We model the film as an array of grains whose grain boundaries can be considered as delta function potentials for electron scattering and the strength of the potentials can be calculated from the measured resistivity of the films. On the other hand, the fiber texture distribution of the the films is obtained from X-ray pole figure measurements, and Monte-Carlo simulations are then performed using this data to determine the average dislocation density at the grain boundaries due to the grain to grain crystallographic mismatch. We show that the transmittance coefficient for electron scattering, and therefore the film resistivity, is a monotonically increasing function of the average dislocation density. We therefore conclude that the structure of grain boundaries in a thin film provides the necessary mechanism by which the resistivity of an FCC cubic metal can depend on the texture.

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