X-ray diffraction study of the effect of boron on lattice properties of Ni76Al24

1993 ◽  
Vol 8 (4) ◽  
pp. 741-744 ◽  
Author(s):  
Mohan P.V. Rao ◽  
Murthy K. Satyanarayana ◽  
S.V. Suryanarayana ◽  
Naidu S.V. Nagender
Keyword(s):  
Diffraction Study ◽  
Single Phase ◽  
Lattice Parameter ◽  
Small Addition ◽  
X Ray Diffraction ◽  
Fault Probability ◽  
Two Phase ◽  
X Ray ◽  
Al Content ◽  
Stacking Fault Probability

A small addition of boron is suggested to increase the ductility of the polycrystalline Ni3Al when the Al content is less than 25 at.%. Both metallographic and x-ray investigation have shown the alloys of Ni3Al (24 at.% Al) containing 0.20, 0.42, 0.79, 0.98, and 1.22 at.% B to be of single phase and that of 1.76 at.% B to be of two phase. With the addition of boron, the lattice parameter of the Ni3Al phase is found to increase. Microhardness measurements indicate that initially the hardness decreases for the alloy of 0.20 at.% B, while for the rest of the single phase alloys the hardness is found to increase with further addition of boron. The addition of boron increases the deformation stacking fault probability value except for the alloy with 0.20 at.% B.

Hydride structures in Ti-aluminides subjected to high temperature and hydrogen pressure charging conditions

1991 ◽  
Vol 6 (6) ◽  
pp. 1230-1237 ◽  
Author(s):  
D. Legzdina ◽  
I.M. Robertson ◽  
H.K. Birnbaum
Keyword(s):  
Single Phase ◽  
Vacuum Annealing ◽  
Lattice Parameter ◽  
Matrix Composition ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
The Matrix ◽  
Diffraction Patterns ◽  
Fcc Structure

The distribution and chemistry of hydrides produced in single and dual phase alloys with a composition near TiAl have been investigated by using a combination of TEM and x-ray diffraction techniques. The alloys were exposed at 650 °C to 13.8 MPa of gaseous H2 for 100 h. In the single-phase gamma alloy, large hydrides preferentially nucleated on the grain boundaries and matrix dislocations and a population of small hydrides was distributed throughout the matrix. X-ray and electron diffraction patterns from these hydrides indicated that they have an fcc structure with a lattice parameter of 0.45 nm. EDAX analysis of the hydrides showed that they were enriched in Ti. The hydrides were mostly removed by vacuum annealing at 800 °C for 24 h. On dissolution of the hydrides, the chemistry of hydride-free regions of the grain boundary returned to the matrix composition, suggesting that Ti segregation accompanied the hydride formation rather than Ti enrichment causing the formation of the hydride. The hydrogen content in the two-phase (γ-α2) alloy was approximately three times that of the single phase alloy, which was presumably a consequence of the presence of the α2-Ti3Al phase in the two-phase alloy. The hydrides in the two-phase material were shown by x-ray diffraction to have an fcc structure and were removed on annealing in vacuum at 800 °C for 24 h.

NEUTRON DIFFRACTION STUDY ON (Bi−Pb)2Sr2Ca2Cu3O10

1990 ◽  
Vol 04 (12) ◽  
pp. 791-794 ◽  
Author(s):  
YANG JI-LIAN ◽  
YE CHUN-TANG ◽  
ZHANG BAI-SHENG ◽  
LI JI-ZHOU ◽  
KANG JIAN ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Diffraction Study ◽  
Single Phase ◽  
Polycrystalline Sample ◽  
Neutron Diffraction Study ◽  
Structure Study ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The polycrystalline sample of (Bi–Pb)2Sr2Ca2Cu3O10 with Tc=107 K was prepared. The X-ray diffraction proved that the sample is single phase. The crystal structure study on the sample has been carried out by neutron diffraction. The result shows that its structure is tetragonal body-centre structure with space group of I4/mmm, containing a few oxygen atoms at 4e site in Bi–Pb layers.

Hardness evolution of Al–Cr–N coatings under thermal load

2008 ◽  
Vol 23 (11) ◽  
pp. 2880-2885 ◽  
Author(s):  
Herbert Willmann ◽  
Paul H. Mayrhofer ◽  
Lars Hultman ◽  
Christian Mitterer
Keyword(s):  
Thermal Load ◽  
Structural Changes ◽  
Single Phase ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Al Content ◽  
Annealing Temperatures ◽  
Transmission Electron

Microstructure and hardness evolution of arc-evaporated single-phase cubic Al0.56Cr0.44N and Al0.68Cr0.32N coatings have been investigated after thermal treatment in Ar atmosphere. Based on a combination of differential scanning calorimetry and x-ray diffraction studies, we can conclude that Al0.56Cr0.44N undergoes only small structural changes without any decomposition for annealing temperatures Ta ⩽ 900 °C. Consequently, the hardness decreases only marginally from the as-deposited value of 30.0 ± 1.1 GPa to 29.4 ± 0.9 GPa with Ta increasing to 900 °C, respectively. The film with higher Al content (Al0.68Cr0.32N) exhibits formation of hexagonal (h) AlN at Ta ⩾ 700 °C, which occurs preferably at grain boundaries as identified by analytical transmission electron microscopy. Hence, the hardness increases from the as-deposited value of 30.1 ± 1.3 GPa to 31.6 ± 1.4 GPa with Ta = 725 °C. At higher temperatures, where the size and volume fraction of the h-AlN phase increases, the hardness decreases to 27.5 ± 1.0 GPa with Ta = 900 °C.

X-ray diffraction study of an as-grown crystal of a two-phase sample of Lu0.65Ca0.35F2.65

2014 ◽  
Vol 59 (6) ◽  
pp. 874-877
Author(s):  
T. S. Chernaya ◽  
N. B. Bolotina ◽  
I. A. Verin ◽  
B. P. Sobolev
Keyword(s):  
Diffraction Study ◽  
Grown Crystal ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Phase Sample

Oxidation Induced Anisotropic Deformation in Perfect Si Crystals. Dynamical X-Ray Diffraction Study

1982 ◽  
Vol 37 (5) ◽  
pp. 433-436
Author(s):  
J. Burgeat ◽  
R. Caciuffo ◽  
J. Primot ◽  
F. Rustichelli
Keyword(s):  
Diffraction Study ◽  
Diffraction Pattern ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Thickness ◽  
Anisotropic Deformation

Double X-ray diffractometry has been used to investigate perfect Si crystals of different orientations, on which SiCO2 layers of different thickness were grown. For the (111) and (110) orientations no appreciable modification of the theoretical diffraction pattern is observed. An important modification, which depends on the SiO2 thickness, appears however for the (100) orientation. The observed effect does not change when the SiO2 is removed and can be interpreted as an enhancement of the lattice parameter.

X-Ray Diffraction Studies of the Bureau of Standards Rubber Fractions

1934 ◽  
Vol 7 (3) ◽  
pp. 503-504
Author(s):  
George L. Clark ◽  
W. J. Warren ◽  
W. H. Smith
Keyword(s):  
Diffraction Study ◽  
Diffraction Pattern ◽  
Phase Model ◽  
Chain Model ◽  
X Ray Diffraction ◽  
Structural Differentiation ◽  
Flexible Chain ◽  
Two Phase ◽  
X Ray ◽  
Crystal Fiber

Abstract At the request of Dr. Washburn, a careful preliminary x-ray diffraction study has been completed on various samples of rubber fractions prepared at the Bureau of Standards by the methods already described. The results are so interesting, especially in structural differentiation between the ether-soluble (sol-rubber) and the ether-insoluble (gel-rubber) hydrocarbons, and in producing new data bearing upon the several theories of the structure of whole rubber, that it has seemed desirable to record very briefly some of the more important observations. It will be recalled that native rubber, raw, purified, or vulcanized, gives a typical liquid halo or “amorphous” type of diffraction pattern in the unstretched condition, which changes to the characteristic crystal fiber pattern when the rubber specimen is stretched. Upon the basis of these facts, several theories of the structure of the rubber hydrocarbon have been proposed: the folded or spiral molecules model; the fringe model (bundles of molecular chains with frayed ends); the flexible chain model; and the very familiar two-phase model.

scholarly journals The Polythermal Section of Ti-22Al-xNb (30-78at.%Ti) in Ti–Al–Nb System

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 871
Author(s):  
Yun Zhao ◽  
Li-Bin Liu ◽  
Li-Gang Zhang ◽  
Jia-Jun Yang ◽  
Patrick J. Masset
Keyword(s):  
Single Phase ◽  
Invariant Reaction ◽  
Polythermal Section ◽  
Electron Probe Micro Analysis ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Three Phase ◽  
Micro Analysis ◽  
O Phase

The polythermal section of Ti-22Al-xNb (30–78 at.% Ti) in the Ti-Al-Nb system was studied using X-ray diffraction analysis (XRD), differential thermal analysis (DSC), and electron probe micro-analysis (EPMA). No new ternary compounds were found in this work. The polythermal section has five three-phase regions, nine two-phase regions, and three single-phase regions. The O phase transition is confirmed to occur below 1000 °C. A four-phase invariant reaction β + σ → O + δ was found at 931 °C.

X-ray diffraction peak-broadening analysis of (La-M)2CuO4 high-Tc superconductors

1993 ◽  
Vol 8 (1) ◽  
pp. 2-6 ◽  
Author(s):  
Davor Balzar ◽  
Hassel Ledbetter ◽  
Alexana Roshko
Keyword(s):  
Diffraction Peak ◽  
Line Profiles ◽  
X Ray Diffraction ◽  
High Tc Superconductors ◽  
Fault Probability ◽  
High Tc ◽  
X Ray ◽  
Peak Broadening ◽  
Crystallographic Symmetry ◽  
Stacking Fault Probability

An X-ray diffraction peak-broadening analysis of four oxides is described: La2CuO4 and La1.85M0.15CuO4 (M = Ca,Ba,Sr) high-Tc superconductors. The diffraction line profiles were fitted with a convolution of specimen and instrumental functions, and the specimen peakbroadening angular dependence was analyzed with the Warren-Averbach method. It was found that microstrains and incoherently diffracting domains are highly anisotropic. In the superconductors, stacking-fault probability increases with increasing Tc; microstrain decreases. In La2CuO4, different broadening of (h00) and (0k0) reflections is not caused by stacking faults; it might arise from lower crystallographic symmetry.

Microstructure and Mechanical Properties of Cr1-xAlxN Coating

2012 ◽  
Vol 531 ◽  
pp. 3-6
Author(s):  
C.L. Zhong ◽  
L.E. Luo
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Lattice Parameter ◽  
Reactive Magnetron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Compound Coating ◽  
Cubic Structure

A series of Cr1-xAlxN coatings were deposited by reactive magnetron sputtering. The content, microstructure and the hardness of the thin films were characterized respectively with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and nanoindentor. The effect of Al content on the microstructure and hardness was studied. It was found that Cr1-xAlxN compound coating exhibits a cubic structure with (1 1 1) preferred orientations and that the lattice parameter of Cr1-xAlxN coatings decrease with the increase of Al content. The hardness of Cr1-xAlxN compound coating is higher than that of CrN and increases with the increase of Al content.

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