Spinodal Decomposition in Fe-Cr Alloys

2011 ◽  
Vol 172-174 ◽  
pp. 443-448
Author(s):  
Orlando Soriano Vargas ◽  
Erika O. Avila Davila ◽  
Victor M. Lopez-Hirata ◽  
Maribel L. Saucedo-Muñoz
Keyword(s):  
Solid Solution ◽  
Mechanical Behavior ◽  
Spinodal Decomposition ◽  
Growth Kinetics ◽  
Supersaturated Solid Solution ◽  
Rich Phase ◽  
Hardening Behavior ◽  
Plate Shape ◽  
Kinetics Of ◽  
Preferential Alignment

The hardening behavior of precipitation was studied during aging of Fe-Cr alloys. This mechanical behavior is associated with the nanometric modulation structure of the coherent decomposed Fe-rich and Cr-rich phases formed by the spinodal decomposition of the supersaturated solid solution. The growth kinetics of spinodal decomposition was very slow and it increased during coarsening stage. The morphology of decomposed phases consisted of an interconnected irregular shape with no preferential alignment for short aging times and a further aging caused the change to a plate shape of the decomposed Cr-rich phase aligned in the <110> directions of the Fe-rich matrix. The rapid increase in hardness and embrittlement seem to be associated with the coherency and nanometer size of the spinodally-decomposed phases in the aged alloys.

Synthesis of Nanocrystalline Ag-Cu Supersaturated Solid Solution by Mechanical Alloying

2010 ◽  
Vol 92 ◽  
pp. 271-276 ◽  
Author(s):  
Liang Feng Li ◽  
Tai Qiu ◽  
Jian Yang ◽  
Yong Bao Feng
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Mechanical Alloying ◽  
Solid Solutions ◽  
Supersaturated Solid Solution ◽  
Main Peak ◽  
Rich Phase ◽  
Transmission Electron ◽  
Supersaturated Solid Solutions ◽  
Xrd Patterns

Nanocrystalline Ag-28Cu supersaturated solid solution is prepared by mechanical alloying (MA) using a planetary ball mill. The mechanical alloyed powders are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and differential scanning calorimeter (DSC). XRD patterns show that the main peak of Ag-28Cu supersaturated solid solution exists at about 2θ=39° when the milling time is 30h. HRTEM images show that the grain sizes of as-prepared solid solutions have distributions from 10nm to 15nm. The interplanar spacing of (111) plane for fcc Ag-28Cu supersaturated solid solution is about 2.24Å. DSC measurement result indicates that the melting temperature of Ag-28Cu supersaturated solid solution is 783.8°C. The Ag(Cu) supersaturated solid solutions are in metastable state and they will be transformed into Ag-rich phase and Cu-rich phase simultaneously by annealing at 215°C- 415°C.

Growth Kinetics of an Amorphous Phase Between GaAs and Co

1991 ◽  
Vol 230 ◽  
Author(s):  
F. Y. Shiau ◽  
Y. A. Chang
Keyword(s):  
Amorphous Phase ◽  
Growth Kinetics ◽  
Electron Spectroscopy ◽  
Supersaturated Solid Solution ◽  
Parabolic Rate Constant ◽  
Transmission Electron ◽  
Gaas Structure ◽  
Approximate Composition ◽  
Kinetics Of ◽  
State Amorphization

AbstractSolid-state amorphization reaction between GaAs and Co thin-films was investigated by transmission electron micorscopy and Auger electron spectroscopy. Upon annealing of GaAs/Co thin-film couples at 260–300 °C, an amorphous phase was observed to form. The amorphization was attributed to the openness of the GaAs structure relative to the size of the Co atoms. This allows rapid diffusion of Co into the GaAs lattice and promotes the occurrence of SSAR. Annealing at higher temperatures or for longer times led to the formation of a crystalline phase, designated as the μ-phase which was determined to be a metastable supersaturated solid solution of CoAs exhibiting the B31 structure of the approximate composition of Co(Ga. .48As.52). The growth kinetics of both the amorphous phase and the μ-phase are parabolic in nature. The parabolic rate constant is higher for the μ-phase than for the amorphous phase. The activation energies are 1.47 and 1.35 eV, respectively.

On the Precipitation Behavior at 250 and 300 °C of WE54 Supersaturated Solid Solution

2012 ◽  
Vol 629 ◽  
pp. 85-89 ◽  
Author(s):  
S. Tighiouaret ◽  
H. Azzeddine ◽  
A. Sam ◽  
A. Sari ◽  
B. Alili ◽  
...  
Keyword(s):  
Solid Solution ◽  
Supersaturated Solid Solution ◽  
Precipitation Sequence ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Precipitation Behavior ◽  
X Ray ◽  
The Mean ◽  
Kinetics Of

The current study seeks to further understand the precipitation sequence in a WE54 Mg alloy using in situ X-ray diffraction, micro-hardness and electrical resistivity during ageing at 250 and 300 °C. We show that the mean hardening effect is due to the precipitation of β' and β1metastable phases. The analysis of the kinetics of the precipitation shows that both phases nucleate at grain boundaries and within grains in the form of plates.

Interfacial evolution between Cu and Pb–free Sn–Zn–Ag–Al solders upon aging at 150 °C

2003 ◽  
Vol 18 (8) ◽  
pp. 1795-1803 ◽  
Author(s):  
Shou Chang Cheng ◽  
Kwang Lung Lin
Keyword(s):  
Growth Rate ◽  
Intermetallic Compounds ◽  
Aging Time ◽  
Growth Kinetics ◽  
Solder Alloys ◽  
Rich Phase ◽  
Intermetallic Formation ◽  
Interfacial Evolution ◽  
Kinetics Of

The interfacial intermetallic formation at 150 °C between Cu and various solders, including Sn–9Zn, Sn–8.55Zn–1Ag, and Sn–8.55Zn–1Ag–XAl was investigated. The Al contents X of the quaternary solder alloys investigated were 0.01–0.45 wt.%. The compositions and the growth kinetics of intermetallic compounds (IMCs) were investigated. The IMC consisted of three layers for Sn–9Zn/Cu, Sn–Zn–Ag/Cu, and Sn–Zn–Ag–XAl/Cu specimens after aging for 100–600 h. These three layers included the Cu3(Zn, Sn) phase adjacent to the solder, the Cu6(Sn, Zn)5 phase in the middle, and the Cu–rich phase near to Cu. For long–term aging time over 1000 h, the Cu6(Sn, Zn)5 phase grew, while the Cu3(Zn, Sn) phase diminished. Al segregation formed in the IMC for all of the Sn–Zn–Ag–XAl/Cu specimens after aging.Cracks formed, when aged for 1000 h, at the solder/IMC interface or within the IMC layer for the following solders: Sn–9Zn, Sn–8.55Zn–1Ag, Sn–8.55Zn–1Ag–0.1Al, Sn–8.55Zn–1Ag–0.25Al, and Sn–8.55Zn–1Ag–0.45Al. The crack was not detected up to 3000 h for the Sn–8.55Zn–1Ag–0.01Al/Cu couple, of which the IMC growth rate was the slowest among all solders.

GROWTH KINETICS OF Cu(Al) SOLID SOLUTION IN Al/Cu DIFFUSION COUPLES

2004 ◽  
Vol 11 (03) ◽  
pp. 337-340 ◽  
Author(s):  
E. B. HANNECH ◽  
N. LAMOUDI ◽  
A. GASMI
Keyword(s):  
Solid Solution ◽  
Growth Kinetics ◽  
Early Stage ◽  
Pure Aluminum ◽  
Layer Growth ◽  
Solid Solution Phase ◽  
Diffusion Couples ◽  
Phase Layer ◽  
Initial Stage ◽  
Kinetics Of

The growth kinetics of the solid solution phase of aluminum in copper in diffusion couples of pure aluminum and copper has been investigated at 425°C using a scanning electron microscope. In the initial stage, the phase layer growth was found to obey the parabolic law, indicating that the rate-controlling process is diffusion. At longer times, the growth rate deviates from the kt-1/2 behavior of the early stage.

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