Coarsening of γ′ in Ni–Al alloys aged under uniaxial compression: II. Diffusion under stress and retardation of coarsening kinetics

2003 ◽  
Vol 51 (17) ◽  
pp. 5013-5019 ◽  
Author(s):  
A.J. Ardell ◽  
S.V. Prikhodko
Keyword(s):  
Uniaxial Compression ◽  
Al Alloys ◽  
Coarsening Kinetics

Kinetics of Coarsening and Solid Sphericity during Reheating of Ductile Iron and Al Alloys

2006 ◽  
Vol 116-117 ◽  
pp. 205-208 ◽  
Author(s):  
P. Babaghorbani ◽  
S. Salarfar ◽  
Mahmoud Nili-Ahmadabadi
Keyword(s):  
Cast Iron ◽  
Solid State ◽  
Ostwald Ripening ◽  
Ductile Cast Iron ◽  
Al Alloys ◽  
Solid Particles ◽  
Coarsening Kinetics ◽  
Semi Solid ◽  
Reheating Process ◽  
Kinetics Of

Reheating process in the semi-solid state is a very important step in the thixoforming process. In this research semi-solid ductile cast iron and Al alloys (Al-2.5Si, Al356) prepared by inclined plate method, were reheated to examine the effect of reheating conditions on the microstructure and coarsening kinetics of the alloys. For ductile cast iron, solid fraction at different reheating temperatures and holding times was obtained and based on these results the optimum reheating temperature range was determined. In the case of Al alloys increase of holding time in the semi-solid state, leads to increase of liquid fraction, solid grain size and improvement of sphericity of solid particles. In addition, the results show that coarsening kinetics of microstructures of both alloys during reheating was diffusion controlled and can be mostly treated by Ostwald ripening theory.

scholarly journals Temperature Dependence of the γ/γ′ Interfacial Energy in Binary Ni–Al Alloys

2021 ◽  
Author(s):  
Alan J. Ardell
Keyword(s):  
Temperature Dependence ◽  
Comprehensive Evaluation ◽  
Chemical Diffusion ◽  
Interfacial Free Energy ◽  
Al Alloys ◽  
Published Data ◽  
Liquid Region ◽  
Theoretical Predictions ◽  
Coarsening Kinetics ◽  
Increasing Temperature

AbstractPublished data on the coarsening kinetics of γ′ (Ni3Al) precipitates in binary Ni–Al alloys aged at 12 temperatures ranging from 773 K to 1073 K are analyzed to provide a comprehensive evaluation of the temperature dependence of the γ/γ′ interfacial free energy, σ. The data are analyzed using equations of the trans-interface-diffusion-controlled (TIDC) theory of coarsening, with temporal exponent n = 2.4. The results show that σ decreases with increasing temperature, T. A linear empirical equation is fitted to the data on σvsT; it extrapolates to σ = 0 in the liquid region of the Ni–Al phase diagram, as it should do. A quantitative temperature-dependent transition radius, rtrans, is calculated; it depends on the product of the interface width and the ratio of the chemical diffusion coefficients in the γ phase and interface regions. Applying the TIDC coarsening equations to calculate σ is justified when the average radius, 〈r〉, satisfies the condition 〈r〉 < rtrans, which is valid for all the data used in the fit. The data on σvsT are compared with theoretical predictions. The results are discussed in the context of previous work, as well as with values of σ obtained through analyses using the equations of traditional LSW coarsening kinetics, n = 3.

Coarsening kinetics of coherent precipitates in Ni-Al-Mo and Fe-Ni-Al alloys

1997 ◽  
Vol 238 (1) ◽  
pp. 13-22 ◽  
Author(s):  
H.A. Calderon ◽  
G. Kostorz ◽  
Y.Y. Qu ◽  
H.J. Dorantes ◽  
J.J. Cruz ◽  
...  
Keyword(s):  
Al Alloys ◽  
Coarsening Kinetics ◽  
Kinetics Of

Mechanical responses and dynamic failure of nanostructure Cu–Al alloys under uniaxial compression

2017 ◽  
Vol 114 ◽  
pp. 147-160 ◽  
Author(s):  
Jianguo Li ◽  
Yulong Li ◽  
Chongxiang Huang ◽  
Tao Suo
Keyword(s):  
Uniaxial Compression ◽  
Al Alloys ◽  
Dynamic Failure ◽  
Mechanical Responses

Three-dimensional phase-field simulations of coarsening kinetics of γ′ particles in binary Ni–Al alloys

2004 ◽  
Vol 52 (9) ◽  
pp. 2837-2845 ◽  
Author(s):  
J.Z. Zhu ◽  
T. Wang ◽  
A.J. Ardell ◽  
S.H. Zhou ◽  
Z.K. Liu ◽  
...  
Keyword(s):  
Phase Field ◽  
Three Dimensional ◽  
Al Alloys ◽  
Coarsening Kinetics ◽  
Kinetics Of

Observation of faint contrast at planar faults in alloys

1978 ◽  
Vol 36 (1) ◽  
pp. 340-341
Author(s):  
K. Kuroda ◽  
Y. Tomokiyo ◽  
T. Kumano ◽  
T. Eguchi
Keyword(s):  
Reciprocal Lattice ◽  
Beam Theory ◽  
Al Alloys ◽  
Small Displacement ◽  
Electron Microscopic ◽  
Lattice Vector ◽  
Fringe Contrast ◽  
Planar Fault ◽  
Lattice Displacement ◽  
The Many

The contrast in electron microscopic images of planar faults in a crystal is characterized by a phase factor , where is the reciprocal lattice vector of the operating reflection, and the lattice displacement due to the fault under consideration. Within the two-beam theory a planar fault with an integer value of is invisible, but a detectable contrast is expected when the many-beam dynamical effect is not negligibly small. A weak fringe contrast is also expected when differs slightly from an integer owing to an additional small displacement of the lattice across the fault. These faint contrasts are termed as many-beam contrasts in the former case, and as ε fringe contrasts in the latter. In the present work stacking faults in Cu-Al alloys and antiphase boundaries (APB) in CuZn, FeCo and Fe-Al alloys were observed under such conditions as mentioned above, and the results were compared with the image profiles of the faults calculated in the systematic ten-beam approximation.

Microstructure of an extruded rapidly solidified Al-8Fe-2Mo alloy

1986 ◽  
Vol 44 ◽  
pp. 548-549
Author(s):  
W. T. Donlon ◽  
J. E. Allison ◽  
S. Shinozaki
Keyword(s):  
Electron Microscopy ◽  
Automotive Industry ◽  
Fuel Economy ◽  
High Strength ◽  
Al Alloys ◽  
Light Weight ◽  
Thin Sections ◽  
Strength And Durability ◽  
Rapidly Solidified ◽  
Whitney Aircraft

Light weight materials which possess high strength and durability are being utilized by the automotive industry to increase fuel economy. Rapidly solidified (RS) Al alloys are currently being extensively studied for this purpose. In this investigation the microstructure of an extruded Al-8Fe-2Mo alloy, produced by Pratt & Whitney Aircraft, Goverment Products Div. was examined in a JE0L 2000FX AEM. Both electropolished thin sections, and extraction replicas were examined to characterize this material. The consolidation procedure for producing this material included a 9:1 extrusion at 340°C followed by a 16:1 extrusion at 400°C, utilizing RS powders which have also been characterized utilizing electron microscopy.

THE FORMATION OF VACANCIES IN ORDERED Fe-Al ALLOYS WITH B2 STRUCTURE

1977 ◽  
Vol 38 (C7) ◽  
pp. C7-364-C7-364 ◽  
Author(s):  
D. PARIS ◽  
P. LESBATS
Keyword(s):  
Al Alloys ◽  
B2 Structure
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