Application of Hrem in Studying Amorphisation of Intermetallic Compounds

1985 ◽  
Vol 62 ◽  
Author(s):  
D. E. Luzzi ◽  
H. Mori ◽  
H. Fujita ◽  
M. Meshii
Keyword(s):  
High Resolution ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Electron Irradiation ◽  
Driving Force ◽  
Amorphous Materials ◽  
Alloy System ◽  
Amorphous Structure ◽  
Ti Alloy ◽  
Special Significance

ABSTRACTElectron irradiation induces many intermetallic compounds to become amorphous. As this irradiation is capable of producing only isolatedpoint defects for each collision event, an understanding of this amorphisation proqess has a special significance with respect to the understanding of amorphous materials. This paper will report the results of HREM observations of an intermetallic compound in the Cu-Ti alloy system. High resolution micrographs will be presented to demonstrate that the energy associated with the irradiation induced chemical disordering is the major driving force in the amorphisation process. Also, the utility of the HREM in the study of amorphisation and the amorphous structure will be discussed.

High-resolution electron microscopy of amorphization of Cu4 Ti3

1986 ◽  
Vol 1 (5) ◽  
pp. 617-628 ◽  
Author(s):  
D.E. Luzzi ◽  
M. Meshii
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Intermetallic Compound ◽  
Driving Force ◽  
High Resolution Electron Microscopy ◽  
Amorphous Structure ◽  
Crystalline Region ◽  
Fringe Contrast ◽  
Chemical Order ◽  
Resolution Electron

The electron irradiation-induced, crystalline-to-amorphous transition was studied in the intermetallic compound Cu4Ti3 by high-resolution electron microscopy. Using highresolution maps from the crystalline region into the amorphized region, the amorphization process and the amorphous structure were examined. The extent of chemical order in crystalline regions just prior to amorphization was studied by simultaneously imaging superlattice and fundamental lattice fringe contrast. The chemical order continuously decreased in these regions but faint superlattice contrast was recognized as long as the crystalline feature remained on the image, supporting the theory that chemical disordering is the major driving force for amorphization. The amorphization process appears to be evolutionary, leading to a nanocrystalline type of amorphous structure. A model of the amorphization process is proposed based on the present results and those from previous studies.

Morphology of wetting reactions of SnPb alloys on Cu as a function of alloy composition

1998 ◽  
Vol 13 (1) ◽  
pp. 37-44 ◽  
Author(s):  
C. Y. Liu ◽  
K. N. Tu
Keyword(s):  
Free Energy ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Driving Force ◽  
Alloy Composition ◽  
Wetting Angle ◽  
Compound Formation ◽  
Side Band ◽  
Intermetallic Compound Formation ◽  
Pure Sn

We have investigated the wetting angle, side band growth, and intermetallic compound formation of seven SnPb alloys on Cu ranging from pure Sn to pure Pb. The wetting angle has a minimum near the middle composition and increases toward pure Sn and pure Pb, but the side band growth has a maximum near the middle composition. The intermetallic compounds formed are Cu6Sn5 and Cu3Sn for the eutectic and high-Sn alloys, yet for the high-Pb alloys, only Cu3Sn can be detected. While no intermetallic compound forms between Cu and pure Pb, the latter nevertheless wets the former with an angle of 115°. The driving force of a wetting reaction, which may be affected by the free energy gain in compound formation, is discussed by assuming that rate of compound formation is fast.

Formation of Amorphous Graded Structure in Bi3Pb7 Intermetallic Compounds under Strong Gravitational Field

2009 ◽  
Vol 289-292 ◽  
pp. 357-360 ◽  
Author(s):  
Tsutomu Mashimo ◽  
Yusuke Iguchi ◽  
Rabaya Bagum ◽  
Tomokazu Sano ◽  
S. Takeda ◽  
...  
Keyword(s):  
Gravitational Field ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Amorphous Structure ◽  
Strong Gravitational Field ◽  
Graded Structure ◽  
Homogeneous Phase ◽  
Graded Structures ◽  
Gravity Direction

A visible four-layers structure with anomalous nano-sturucture was formed from a homogeneous -phase Bi3Pb7 intermetallic compound under a strong gravitational field (1.02x106 G, 130°C, 100 hours). In the 4th layer (lowest-gravity region), pure Bi particles precipitate. In the 2nd 3rd layers, composition graded structures, where Pb content increased along the gravity direction, were formed. It was found that the very broad XRD peak appeared in the 2nd layer, which indicated that an amorphous structure was contained.

Amorphisation Tendency of Intermetallic Compounds Under Electron Irradiation

1986 ◽  
Vol 74 ◽  
Author(s):  
D. E. Luzzi ◽  
M. Meshii
Keyword(s):  
Crystal Structure ◽  
Intermetallic Compounds ◽  
Electron Irradiation ◽  
Alloy System ◽  
Metal Compounds ◽  
Complex Crystal Structure ◽  
In Situ Experiments ◽  
Binary Alloy System ◽  
Disordered Crystal

AbstractThe chemical disordering model for the electron irradiation induced crystalline to amorphous (C-A) transition was previously developed using in-situ experiments in the intermetallic compounds of the Cu-Ti binary alloy system. In the context of this model, a rule was developed which predicts the amorphisation tendency of these and other binary intertransition metal compounds with an accuracy of 92% in the 38 compounds studied to date. Two aspects of this rule, the composition of the compound and the crystal structure are examined through a first approximation computer comparison of ordered, partially ordered, and disordered crystal structures. It is found that in bcc based compounds and in complex crystal structure compounds, the ability of the chemical disordering to raise the energy of the crystal is severely inhibited at compound compositions away from 50:50. During the disordering process, the greatest increase of the crystal energy occurs during the early stages of chemical disordering. These results mesh well with the concept of an amorphous transition driven by the energy increase due to chemical disordering.

scholarly journals Radiation-induced crystalline-to-amorphous transition in intermetallic compounds of the CuTi alloy system

1993 ◽  
Vol 194 (2) ◽  
pp. 429-437 ◽  
Author(s):  
N.Q. Lam ◽  
P.R. Okamoto ◽  
M.J. Sabochick ◽  
R. Devanathan
Keyword(s):  
Intermetallic Compounds ◽  
Alloy System ◽  
Ti Alloy ◽  
Radiation Induced

scholarly journals Heat Treatment-Induced Microstructure and Property Evolution of Mg/Al Intermetallic Compound Coatings Prepared by Al Electrodeposition on Mg Alloy from Molten Salt Electrolytes

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1407
Author(s):  
Tianyu Yao ◽  
Kui Wang ◽  
Haiyan Yang ◽  
Haiyan Jiang ◽  
Jie Wei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Mg Alloy ◽  
X Ray Diffraction ◽  
Electron Backscattered Diffraction ◽  
Alloy Matrix ◽  
Comprehensive Properties ◽  
Compound Coatings ◽  
Compound Coating

A method of forming an Mg/Al intermetallic compound coating enriched with Mg17Al12 and Mg2Al3 was developed by heat treatment of electrodeposition Al coatings on Mg alloy at 350 °C. The composition of the Mg/Al intermetallic compounds could be tuned by changing the thickness of the Zn immersion layer. The morphology and composition of the Mg/Al intermetallic compound coatings were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron backscattered diffraction (EBSD). Nanomechanical properties were investigated via nano-hardness (nHV) and the elastic modulus (EIT), and the corrosion behavior was studied through hydrogen evolution and potentiodynamic (PD) polarization. The compact and uniform Al coating was electrodeposited on the Zn-immersed AZ91D substrate. After heat treatment, Mg2Al3 and Mg17Al12 phases formed, and as the thickness of the Zn layer increased from 0.2 to 1.8 μm, the ratio of Mg2Al3 and Mg17Al12 varied from 1:1 to 4:1. The nano-hardness increased to 2.4 ± 0.5 GPa and further improved to 3.5 ± 0.1 GPa. The Mg/Al intermetallic compound coating exhibited excellent corrosion resistance and had a prominent effect on the protection of the Mg alloy matrix. The control over the ratio of intermetallic compounds by varying the thickness of the Zn immersion layer can be an effective approach to achieve the optimal comprehensive performance. As the Zn immersion time was 4 min, the obtained intermetallic compounds had relatively excellent comprehensive properties.

Crystalline-To-Amorphous Transformation of Intermetallic Compounds in the Zr-Fe-M System Induced by Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
Arthur T. Motta ◽  
Lawrence M. Howe ◽  
Paul R. Okamoto
Keyword(s):  
Critical Temperature ◽  
Low Temperature ◽  
Dose Rate ◽  
Intermetallic Compounds ◽  
Electron Energy ◽  
Energy Dependence ◽  
Electron Irradiation ◽  
Critical Temperatures ◽  
Lower Critical Temperature ◽  
Ternary Intermetallic Compounds

AbstractThe binary and ternary intermetallic compounds Zr3Fe, Zr2 Fe, (Zr0.5,Nb0.5)3Fe, Zr3(Fe0.9,Ni0.1) and Zr3(Fe0.5,Ni0.5) were subjected to 900 keV electron irradiation until amorphous to study the change in the dose-to-amorphization with temperature. The critical temperatures were observed to vary with dose rate, and with the type of compound. Hexagonal (Zr0.5,Nb0.5)3Fe had an appreciably lower critical temperature and higher dose to amorphization at low temperature than orthorombic Zr3Fe, whereas other orthorombic Zr3(Fex,NiI-x) compounds were essentially identical in behavior to Zr3Fe. The electron energy dependence of the dose-to-amorphization was studied in Zr3Fe between 250 and 900 keV. The analysis of the results gives displacement energies of EZrd = 26 eV, EFed = 18 eV in the Zr3Fe compound.

A study of Al2Ti precipitation in a Cu-modified Al3Ti alloy

1992 ◽  
Vol 7 (4) ◽  
pp. 876-882 ◽  
Author(s):  
L. Potez ◽  
A. Loiseau ◽  
S. Naka ◽  
G. Lapasset
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Mechanical Behavior ◽  
Vickers Microhardness ◽  
High Resolution Electron Microscopy ◽  
Nucleation And Growth ◽  
Ti Alloy ◽  
Hardening Effect ◽  
Resolution Electron

An equilibrium precipitation of Al2Ti is shown to occur within a Cu-modified Al2Ti alloy having the L12 structure. This precipitation is analyzed by conventional and high resolution electron microscopy and some insights are given concerning the mechanisms of nucleation and growth of Al2Ti within the L12 matrix. In the meantime, Vickers microhardness tests have been performed as a first approach to the mechanical behavior of this alloy and the results are compared to measurements obtained in an actual single-phased L12 compound. The Al2Ti precipitation seems to have an important hardening effect.

scholarly journals Effect of Small Addition of Cobalt on Magnetic Properties and Internal Stresses Sources in the Form of Free Volumes and Pseudo-Dislocation Dipoles in Fe78CoXSi11-XB11 (x = 0 Or 2) Alloys / Wpływ Nieznacznego Dodatku Kobaltu Na Właściwości Magnetyczne Oraz Źródła Naprężeń Wewnętrznych W Postaci Wolnych Objętości Oraz Pseudodyslokacyjnych Dipoli W Stopach Fe78CoXSi11-XB11 (x = 0 Or 2)

2015 ◽  
Vol 60 (4) ◽  
pp. 3095-3100 ◽  
Author(s):  
M. Szota
Keyword(s):  
Magnetic Properties ◽  
Amorphous Materials ◽  
Amorphous Structure ◽  
Small Addition ◽  
Structural Defects ◽  
Internal Stresses ◽  
Structure Defects ◽  
Alloy Addition ◽  
Application Potential ◽  
Technical Industry

Amorphous materials in the form of tapes, despite being discovered more than half a century ago, are still the object of interest for materials engineers and electro-technical industry. They possess a great application potential, and are constantly studied for new variations. Due to the different structure from the commonly manufactured textured FeSi sheets, FeCoB based amorphous alloys demonstrate very good, so called soft magnetic properties. This paper presents the results of studying the structure and magnetic properties of tapes of Fe78CoxSi11-xB11(X = 0 or 2) alloys of amorphous structure. In addition, the effect of Co alloy addition on the type of structural defects in the area of ferromagnetic saturation approach was examined. It was found that a small addition of Co affects the increase of saturation magnetization value, as well as the distribution of magnetization vectors within the stresses sources in form of structure defects.

Influence of Interfacial Copper on the Ti-SiO2 Reaction During Nitridation of Cu-Ti Films

1995 ◽  
Vol 398 ◽  
Author(s):  
Daniel Adams ◽  
T.L. Alford ◽  
N.D. Theodore ◽  
T. Laursen ◽  
S.W. Russell ◽  
...  
Keyword(s):  
Free Surface ◽  
High Resolution ◽  
Consumption Rate ◽  
Catalytic Effect ◽  
Energy Dispersive ◽  
Ti Alloy ◽  
Alloy Films ◽  
X Ray ◽  
20 Nm ◽  
Ti Films

ABSTRACTCu(90 nm)/Ti(20 nm) bilayers and Cu(Ti 27 at.%) alloy films were deposited on SiO2 and annealed in an NH3 ambient at temperatures 400–700° C for 30 min. During annealing Ti segregated to both the free surface and the alloy/SiO2 interface. At the surface Ti reacted with NH3 to form TiN, whereas at the interface the Ti reacted with the SiO2 to form a TiO/Ti5Si3 structure. High resolution energy dispersive x-ray analysis revealed the presence of interfacial Cu between the Ti-silicide and Ti-oxide layers at temperatures greater than 450°C. Using Cu-Ti alloy films enhanced the Si02 consumption rate by a factor of 3-4 compared to that of pure Ti. It is suggested that the interfacial Cu is responsible for the increased rate. It is plausible that an interfacial Cu2O component has a catalytic effect on the Ti- SiO2 reaction.

Sign in / Sign up

Export Citation Format

Share Document