Crystal dynamics of nickel–iron and copper–zinc alloys

1969 ◽  
Vol 47 (10) ◽  
pp. 1117-1131 ◽  
Author(s):  
E. D. Hallman ◽  
B. N. Brockhouse
Keyword(s):  
Diffraction Method ◽  
Face Centered Cubic ◽  
Frequency Distributions ◽  
Zinc Alloys ◽  
Mean Frequency ◽  
Nickel Iron ◽  
The Face ◽  
Copper Zinc ◽  
Face Centered ◽  
Frequency Ratios

Using inelastic scattering of slow neutrons, the frequency-wavevector dispersion relations for the lattice vibrations in the face-centered cubic alloys Ni3Fe, Ni0.5Fe0.5, Ni0.3Fe0.7, and Cu3Zn have been measured at 296 °K. Measurements were also made at 573 °K for the Ni0.3Fe0.7 alloy. The results for the nickel–iron alloys are very similar to those for nickel, with mean frequency ratios (alloy/nickel) of 0.990, 0.950, 0.953 for the Ni3Fe, Ni0.5Fe0.5, and Ni0.3Fe0.7 alloys respectively. Significant deviations of the limiting slopes of the dispersion curves for Ni0.3Fe0.7 from velocities reported by Alers et al. from ultrasonic measurements are thought to be caused by magnetic contributions which are small at the frequencies measured here. The temperature dependence of the frequencies for Ni0.3Fe0.7 is consistent with that observed for nickel. For Cu3Zn, the results are similar to those for copper; except that the mean frequency ratio (alloy/copper) is 0.932. A neutron diffraction method was used to characterize the homogeneity and composition of the alloys. Born – von Kármán fits to the data, the frequency distributions, and Debye temperature vs. temperature relations are also given.

scholarly journals Invariant plastic deformation mechanism in paramagnetic nickel–iron alloys

2021 ◽  
Vol 118 (14) ◽  
pp. e2023181118
Author(s):  
Zhihua Dong ◽  
Wei Li ◽  
Stephan Schönecker ◽  
Bin Jiang ◽  
Levente Vitos
Keyword(s):  
Plastic Deformation ◽  
High Temperature ◽  
Deformation Mechanism ◽  
Elevated Temperatures ◽  
Face Centered Cubic ◽  
Nickel Iron ◽  
Plastic Deformation Mechanism ◽  
The Face ◽  
Face Centered ◽  
Scientific Attention

The Invar anomaly is one of the most fascinating phenomena observed in magnetically ordered materials. Invariant thermal expansion and elastic properties have attracted substantial scientific attention and led to important technological solutions. By studying planar faults in the high-temperature magnetically disordered state of Ni1−cFec, here we disclose a completely different anomaly. An invariant plastic deformation mechanism is characterized by an unchanged stacking fault energy with temperature within wide concentration and temperature ranges. This anomaly emerges from the competing stability between the face-centered cubic and hexagonal close-packed structures and occurs in other paramagnetic or nonmagnetic systems whenever the structural balance exists. The present findings create a platform for tailoring high-temperature properties of technologically relevant materials toward plastic stability at elevated temperatures.

A study of interface sliding at F.C.C.-B.C.C. boundaries in a Cu-Zn alloy

1978 ◽  
Vol 36 (1) ◽  
pp. 422-423
Author(s):  
F. Monchoux ◽  
A. Rocher ◽  
J.L. Martin
Keyword(s):  
Face Centered Cubic ◽  
Creep Tests ◽  
High Voltage Electron Microscopy ◽  
Diffusion Treatment ◽  
Voltage Electron ◽  
The Face ◽  
Face Centered ◽  
Interface Sliding ◽  
Zn Alloy ◽  
Made In

Interphase sliding is an important phenomenon of high temperature plasticity. In order to study the microstructural changes associated with it, as well as its influence on the strain rate dependence on stress and temperature, plane boundaries were obtained by welding together two polycrystals of Cu-Zn alloys having the face centered cubic and body centered cubic structures respectively following the procedure described in (1). These specimens were then deformed in shear along the interface on a creep machine (2) at the same temperature as that of the diffusion treatment so as to avoid any precipitation. The present paper reports observations by conventional and high voltage electron microscopy of the microstructure of both phases, in the vicinity of the phase boundary, after different creep tests corresponding to various deformation conditions.Foils were cut by spark machining out of the bulk samples, 0.2 mm thick. They were then electropolished down to 0.1 mm, after which a hole with thin edges was made in an area including the boundary

MINIMAL KNOTTING NUMBERS

2009 ◽  
Vol 18 (08) ◽  
pp. 1159-1173 ◽  
Author(s):  
CASEY MANN ◽  
JENNIFER MCLOUD-MANN ◽  
RAMONA RANALLI ◽  
NATHAN SMITH ◽  
BENJAMIN MCCARTY
Keyword(s):  
The Body ◽  
Computer Algorithm ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Lattice ◽  
The Face ◽  
Face Centered ◽  
Body Centered Cubic Lattice

This article concerns the minimal knotting number for several types of lattices, including the face-centered cubic lattice (fcc), two variations of the body-centered cubic lattice (bcc-14 and bcc-8), and simple-hexagonal lattices (sh). We find, through the use of a computer algorithm, that the minimal knotting number in sh is 20, in fcc is 15, in bcc-14 is 13, and bcc-8 is 18.

Poisson's Ratio for Central-Force Polycrystals

1976 ◽  
Vol 31 (12) ◽  
pp. 1539-1542 ◽  
Author(s):  
H. M. Ledbetter
Keyword(s):  
Electron Energy ◽  
Poisson Ratio ◽  
The Body ◽  
Central Force ◽  
Face Centered Cubic ◽  
Polycrystalline Aggregate ◽  
Body Centered Cubic ◽  
The Face ◽  
Predicted Values ◽  
Face Centered

Abstract The Poisson ratio υ of a polycrystalline aggregate was calculated for both the face-centered cubic and the body-centered cubic cases. A general two-body central-force interatomatic potential was used. Deviations of υ from 0.25 were verified. A lower value of υ is predicted for the f.c.c. case than for the b.c.c. case. Observed values of υ for twenty-three cubic elements are discussed in terms of the predicted values. Effects of including volume-dependent electron-energy terms in the inter-atomic potential are discussed.

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