Effect of Gold Addition on the Nanostructure of Amorphous Fe–Zr–B Alloy

2000 ◽  
Vol 15 (6) ◽  
pp. 1271-1279 ◽  
Author(s):  
Y. Zhang ◽  
U. Czubayko ◽  
N. Wanderka ◽  
F. Zhu ◽  
H. Wollenberger
Keyword(s):  
Amorphous Alloys ◽  
Crystallization Process ◽  
Amorphous Matrix ◽  
Early Stage ◽  
Primary Crystallization ◽  
Atom Probe ◽  
Probe Field ◽  
Au Clusters ◽  
Transmission Electron ◽  
Ion Microscopy

The behavior of Au in the course of the primary crystallization process of Fe87Zr7B5Au1 amorphous alloy was examined by use of atom probe field ion microscopy and transmission electron microscopy. In the early stage of crystallization, Au atoms were still distributed uniformly in the amorphous matrix. Au atoms form clusters at a later stage when more α–Fe particles are present. The Au clusters were observed to be separated from α–Fe particles, indicating that Au clusters do not stimulate nucleation of α–Fe particles. During the growth of α–Fe grains, cosegregation of Au and Zr occurred without any influence on the α–Fe grain growth. We conclude that Au addition has no effect on nanocrystallization of Fe–Zr–B amorphous alloys.

APFIM Studies of Nanocrystallizations of Amorphous Alloys

1995 ◽  
Vol 400 ◽  
Author(s):  
K. Hono ◽  
Y. Zhang ◽  
A. Inoue ◽  
T. Sakurai
Keyword(s):  
Amorphous Alloys ◽  
Amorphous Matrix ◽  
Primary Crystallization ◽  
Atom Probe ◽  
Nucleation And Growth ◽  
Cu Alloy ◽  
Nucleation Sites ◽  
Medium Range ◽  
Crystallization Reaction ◽  
Primary Crystals

AbstractThis paper reports recent atom probe analysis results of Fe-Zr-B(-Cu) and Al-Ni-Ce(-Cu) amorphous alloys, in which nanocrystalline microstructures develop by primary crystallization. In these alloy systems, enrichment of slow diffusing solute was found at the interfaces between primary crystals and amorphous matrix during the nucleation and growth stage. In the case of ternary Fe-Zr-B, no evidence for compositional heterogeneities were found prior to the onset of crystallization reaction. On the other hand, clustering of Cu atoms was observed in quaternary Fe-Zr-B-Cu alloy prior to the crystallization reaction. In the ternary Fe-Zr-B alloy, nucleation sites seem to be provided by the quenched-in nuclei which were observed as medium range ordered (MRO) domains by HREM. In the as-quenched Al-Ni-Ce(-Cu) alloy, compositional fluctuations were present from the as-quenched state. These observations suggest that nuclei for primary crystallization are provided in various forms such as MRO domains, solute clusters and compositional heterogeneities.

On The Effect of Au Addition and the Role of B on Nanocrystallization of Fe-Zr-B Amorphous Alloy

1999 ◽  
Vol 580 ◽  
Author(s):  
Y. Zhang ◽  
N. Wanderka ◽  
U. Czubayko ◽  
F. Zhu ◽  
H. Wollenberger
Keyword(s):  
Amorphous Alloy ◽  
Early Stage ◽  
Primary Crystallization ◽  
Atom Probe ◽  
Chemical Compositions ◽  
Probe Field ◽  
Heterogeneous Distribution ◽  
Nucleation Barrier ◽  
Nucleation Sites

AbstractUsing atom probe field ion microscopy (APFIM) we examined the local chemical compositions of Fe-7Zr-5B-lAu and Fe-14B amorphous alloys in the course of primary crystallization. Au rich clusters are formed during primary crystallization of Fe-7Zr-5B-lAu alloy. However, these clusters do not act as nucleation sites for α-Fe particles. In the early stage of primary crystallization, heterogeneities of Fe and B evolve in the amorphous phase. Heterogeneous distribution of B was found in the as-melt-spun Fe-14B amorphous alloy. During primary crystallization, B is highly supersaturated not only in the nanometer sized α-Fe particles in Fe-7Zr-5B-lAu alloy, but also in those of large diameters in Fe-14B alloy. From the results it is concluded that presence of B lowers the nucleation barrier for primary crystallization.

Characterizatiom of spinodally decomposed Fe-30.1% Cr-9.9% Co: Part 1

1986 ◽  
Vol 44 ◽  
pp. 580-581
Author(s):  
L. L. Horton ◽  
M. K. Miller ◽  
S. Spooner
Keyword(s):  
Isothermal Aging ◽  
Small Angle Neutron Scattering ◽  
Atom Probe ◽  
Probe Field ◽  
Solution Treated ◽  
Transmission Electron ◽  
Water Quench ◽  
Complementary Nature ◽  
Ion Microscopy

Transmission Electron Microscopy (TEM), Atom Probe Field-Ion Microscopy (APFIM) and Small Angle Neutron Scattering (SANS) have been used to characterize the microstructure of a commercial Fe-30.1 at.% Cr-9.9 at.% Co alloy. One goal of this investigation was to demonstrate the complementary nature of these techniques in solving a difficult materials problem, the characterization of fine scale spinodally-decomposed structures. The alloy was solution treated at 925°C for 140 min followed by water quenching, isothermal aging at 525°C for times of 2, 8, 24, 72, 192, or 485 h and a final water quench. TEM characterizations were performed with Philips EM400T/FEG, Philips EM430T and JEM 120C instruments.

Characterizatiom of spinodally decomposed Fe-30.1% Cr-9.9% Co: Part 2

1986 ◽  
Vol 44 ◽  
pp. 582-583
Author(s):  
S. Spooner ◽  
L. L. Horton ◽  
M. K. Miller
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Atom Probe ◽  
Real Space ◽  
Probe Field ◽  
Α Phase ◽  
Transmission Electron ◽  
Ion Microscopy

Characteristic distances describing the scale of the spinodal microstructure obtained from Transmission Electron Microscopy (TEM), Atom Probe Field Ion Microscopy (APFIM), and Small Angle Neutron Scattering (SANS) are described and compared. These techniques provide a view of the microstructure either directly in real space or indirectly in reciprocal space. The material and its general microstructure are described in Part 1, elsewhere in these proceedings. Only the decomposition of the ferrite phase into a modulated isotropic microstructure consisting of a chromium-enriched α' phase and an iron-rich a phase is considered in this presentation.

scholarly journals A Study of the Phase Decomposition of Fe-Ni-Al-Mo Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
M.K. Miller ◽  
M.G. Hetherington ◽  
J.R. Weertman ◽  
H.A. Calderon
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atom Probe ◽  
Lattice Parameter ◽  
Al Alloys ◽  
Phase Decomposition ◽  
Probe Field ◽  
Transmission Electron ◽  
The Matrix ◽  
Ion Microscopy

AbstractThe aging of β′ NiAl precipitates in ferritic Fe-Ni-Al alloys has been studied by transmission electron microscopy (TEM) and atom-probe field-ion microscopy (APFIM). The addition of Mo alters the lattice parameter of the phases and segregation of Mo to the interface between the matrix and the particles may alter the interfacial energy. The compositions of the matrix, precipitates and interfaces have been measured by TEM and APFIM. The results are compared.

Decomposition of Unstable Supersaturated Cu90Co10 Solid Solutions

1995 ◽  
Vol 400 ◽  
Author(s):  
Ralf Busch ◽  
Frank Gärtner ◽  
Christine Borchers ◽  
Peter Haasen ◽  
Rüdiger Bormann
Keyword(s):  
Heterogeneous Nucleation ◽  
Atom Probe ◽  
Nucleation And Growth ◽  
Growth Behavior ◽  
Nanometer Scale ◽  
Probe Field ◽  
Chemical Ordering ◽  
Transmission Electron ◽  
Composition Profiles ◽  
Ion Microscopy

AbstractHomogeneous Cu90Co10 alloys were prepared by rapid solidification using the meltspin technique. The decomposition process of this highly supersaturated unstable solid solution was investigated on a nanometer scale using a combination of atom probe field ion microscopy (AP/FIM) analyses and transmission electron microscopy.Annealing of the Cu90Co10 alloys at 440°C for various times leads to the formation of a compositional modulated microstructure within the grains. The composition profiles determined by AP/FIM analyses clearly exclude a classical nucleation and growth behavior of Co-rich particles. The microstructure is modulated with two different wavelengths. In addition, chemical ordering perpendicular to [111] directions of the fee lattice is observed.At the grain boundaries of this alloy, heterogeneous nucleation of pure Co particles is observed. This heterogeneous nucleation process competes with the decomposition within the grains.

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