scholarly journals Microstructure, Hardness, and Elastic Modulus of a Multibeam-Sputtered Nanocrystalline Co-Cr-Fe-Ni Compositional Complex Alloy Film

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3357
Author(s):  
Péter Nagy ◽  
Nadia Rohbeck ◽  
Zoltán Hegedűs ◽  
Johann Michler ◽  
László Pethö ◽  
...  

A nanocrystalline Co-Cr-Ni-Fe compositional complex alloy (CCA) film with a thickness of about 1 micron was produced by a multiple-beam-sputtering physical vapor deposition (PVD) technique. The main advantage of this novel method is that it does not require alloy targets, but rather uses commercially pure metal sources. Another benefit of the application of this technique is that it produces compositional gradient samples on a disk surface with a wide range of elemental concentrations, enabling combinatorial analysis of CCA films. In this study, the variation of the phase composition, the microstructure (crystallite size and defect density), and the mechanical performance (hardness and elastic modulus) as a function of the chemical composition was studied in a combinatorial Co-Cr-Ni-Fe thin film sample that was produced on a surface of a disk with a diameter of about 10 cm. The spatial variation of the crystallite size and the density of lattice defects (e.g., dislocations and twin faults) were investigated by X-ray diffraction line profile analysis performed on the patterns taken by synchrotron radiation. The hardness and the elastic modulus were measured by the nanoindentation technique. It was found that a single-phase face-centered cubic (fcc) structure was formed for a wide range of chemical compositions. The microstructure was nanocrystalline with a crystallite size of 10–27 nm and contained a high lattice defect density. The hardness and the elastic modulus values measured for very different compositions were in the ranges of 8.4–11.8 and 182–239 GPa, respectively.

2007 ◽  
Vol 22 (5) ◽  
pp. 1314-1321 ◽  
Author(s):  
J. Gubicza ◽  
S. Nauyoks ◽  
L. Balogh ◽  
J. Labar ◽  
T.W. Zerda ◽  
...  

Microstructure of sintered nanocrystalline SiC is studied by x-ray line profile analysis and transmission electron microscopy. The lattice defect structure and the crystallite size are determined as a function of pressure between 2 and 5.5 GPa for different sintering temperatures in the range from 1400 to 1800 °C. At a constant sintering temperature, the increase of pressure promotes crystallite growth. At 1800 °C when the pressure reaches 8 GPa, the increase of the crystallite size is impeded. The grain growth during sintering is accompanied by a decrease in the population of planar faults and an increase in the density of dislocations. A critical crystallite size above which dislocations are more abundant than planar defects is suggested.


2007 ◽  
Vol 22 (6) ◽  
pp. 1744-1753 ◽  
Author(s):  
M. D’Incau ◽  
M. Leoni ◽  
P. Scardi

Iron-molybdenum powders ground in a planetary ball mill under different operating conditions were studied by x-ray diffraction line profile analysis using a recently developed whole powder pattern modeling approach. The evolution of the microstructure, expressed in terms of size distribution of coherent scattering domains, average dislocation density, and edge/screw character, shows the importance of the main process parameters: the ratio between jar and main disk rotation speeds, and ball milling time. A characteristic three-stage process is observed, with work hardening followed by particle flattening/bending before nanocrystalline grains form by a fragmentation process triggered by localized deformation. The relationship between lattice defect density and domain size suggests a progressive transition between statistically stored to geometrically necessary dislocations, with the latter mostly present as excess dislocations at the nanodomain boundary.


1997 ◽  
Vol 12 (1) ◽  
pp. 28-37 ◽  
Author(s):  
P. Scardi ◽  
F. C. Matacotta ◽  
V. I. Dediu ◽  
L. Correra

X-ray diffraction line profile analysis (LPA) has been carried out on a set of superconducting thin films of MBa2Cu3O7−δ (MBCO, M = Y, Gd), deposited by pulsed and continuous physical vapor deposition (PVD) techniques on different single-crystal substrates. The choice of appropriate deposition conditions, substrates, and buffer layers promoted a high degree of [00l] preferred orientation, leading to a well-defined columnar grain morphology in the MBCO films. Under such conditions, the LPA of diffraction patterns, collected with the widely spread Bragg–Brentano geometry, gives detailed information on the distributions of coherent scattering domain (crystallite) size and microstrain along the [00l] growth direction; considering the particular MBCO film microstructure, the mean crystallite size () can be regarded as the mean distance between extended planar defects parallel to the film surface. The significance of goes beyond a merely statistical value. As long as the morphology of the films is similar, is found to be strictly connected with the average microstrain by a simple proportionality relation. Moreover, the correlation extends to important superconducting transport parameters, like the transition width ΔTc. These regular behaviors are irrespective of deposition techniques, substrate, and film materials, and are a clear indication of some fundamental relation between the defects and the overall properties of the films.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.


2020 ◽  
Vol 44 (1) ◽  
pp. 32-38
Author(s):  
Hani Shaker ◽  
Muhammad Imran ◽  
Wasim Sajjad

Abstract Chemical graph theory has become a prime gadget for mathematical chemistry due to its wide range of graph theoretical applications for solving molecular problems. A numerical quantity is named as topological index which explains the topological characteristics of a chemical graph. Recently face centered cubic lattice FCC(n) attracted large attention due to its prominent and distinguished properties. Mujahed and Nagy (2016, 2018) calculated the precise expression for Wiener index and hyper-Wiener index on rows of unit cells of FCC(n). In this paper, we present the ECI (eccentric-connectivity index), TCI (total-eccentricity index), CEI (connective eccentric index), and first eccentric Zagreb index of face centered cubic lattice.


2012 ◽  
Vol 60 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Adnan Hossain Khan ◽  
Parimal Bala ◽  
AFM Mustafizur Rahman ◽  
Mohammad Nurnabi

Glycine-Montmorillonite (Gly-MMT) composite has been synthesized through intercalation process using Na-Montmorillonite (Na- MMT) and glycine ethylester hydrochloride. Gly-MMT was employed for the synthesis of dipeptide (Gly-Gly-MMT). Microstructural parameters such as crystallite size, r.m.s. strain (<e2>1/2) and layer disorder parameters such as variation of interlayer spacing (g) and proportion of planes affected by such defects (?) of the samples have been calculated by X-ray line profile analysis. In comparison to Na-MMT the basal spacings (d001) of Gly-MMT and Gly-Gly-MMT were reduced by 2.4Å and 1.8Å respectively. The value of d001 of Gly-Gly-MMT (13.3 Å) suggests the monolayer orientation of dipeptide into interlayer spaces. It is also suggested that more homogeneity in the stacking of silicate layers is attained in Gly-Gly-MMT due to the increased chain length of the dipeptide and orientation in monolayer style.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10331Dhaka Univ. J. Sci. 60(1): 25-29, 2012 (January)


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