Kinetics of defect recovery and long-range ordering in Ni3Al + B—I. Simultaneous recovery and ordering in cold-rolled material

The addition of scandium severely retards the recrystallization of Al-Sc alloys when it is present in the form of fine Al3Sc precipitates. Though many studies have focused on the role of Al3Sc in the deformation and recrystallization of pre-aged or hot deformed Al-Sc alloys, recent studies on the annealing response of solutionized and cold rolled material have shown various possibilities for microstructural stability depending on the relative kinetics of precipitation and recrystallization. In this study, the microstructural evolution of solutionized and cold rolled Al- 2.9wt%Mg-0.16wt%Sc has been followed in order to evaluate the role of imposed strain and annealing temperature on the recrystallization kinetics.

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Evidence of a Correlation Between the Transition Temperature for Ordering and the Activation Energy for Ordering Kinetics in Ni75Al25-xFex Superalloys

MRS Proceedings ◽

10.1557/proc-205-153 ◽

1990 ◽

Vol 205 ◽

Author(s):

R. Kozubski ◽

J. Soltys ◽

M.C. Cadeville ◽

V. Pierron-Bohhes

Keyword(s):

Activation Energy ◽

Transition Temperature ◽

Long Range ◽

Theoretical Models ◽

Considerable Effect ◽

Ordering Kinetics ◽

Current Value ◽

Long Range Ordering ◽

Kinetics Of

AbstractKinetics of long-range ordering was studied in the alloys Ni75Al25-xFex by means of in situ resistometry. The alloys under consideration exhibit a dramatic decrease of the "order-disorder" transition temperature Ttr with increasing X. After the existing theoretical models, the activation energy of long-range ordering should depend on one hand on the energy of ordering - related to Ttr -, and on the other hand, on the current value of the LRO degree. The performed measurements yield an experimental evidence of the above relationships. In addition, a considerable effect of magnetic order on LRO kinetics has also been registered. The results are qualitatively discussed in terms of the model of LRO kinetics in L12 structure proposed by Schoijet and Girifalco.

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Short and Long-Range Ordering of (Ni0.67Cr0.33)1-xFex Alloys Under Electron Irradiation

MRS Proceedings ◽

10.1557/proc-439-373 ◽

1996 ◽

Vol 439 ◽

Cited By ~ 2

Author(s):

E. Frely ◽

B. Beuneu ◽

A. Barbu ◽

G. Jaskierowicz

Keyword(s):

Electron Microscope ◽

Transition Temperature ◽

Long Range ◽

Model Alloy ◽

Resistivity Measurements ◽

Voltage Electron ◽

High Voltage Electron Microscope ◽

Superlattice Peak ◽

Long Range Ordering ◽

Kinetics Of

Abstract(Ni0.67Cr0.33)1-xFex alloys with x = 0, 5 and 10 at.%, have been irradiated at temperatures between 300°C and 500°C with the electrons of a 2.5MeV Van de Graaff accelerator and of a 1MeV High Voltage Electron Microscope (HVEM). All of them have been successively ordered at short and at long range under irradiation. The transition temperature is 525°C for Ni0.61Cr0.34Fe0.05 and 445°C for Ni0.59Cr0.31Fe0.10. An Inconel sample irradiated up to 1 d.p.a. in the 1MeV microscope did not show any superlattice peak although its composition is very close to the 10% iron model alloy. The kinetics of ordering has been followed by resistivity measurements and fitted by the Dienes kinetic model.

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Kinetics of Ordering in Cu3Au

MRS Proceedings ◽

10.1557/proc-481-297 ◽

1997 ◽

Vol 481 ◽

Cited By ~ 2

Author(s):

H. Lang ◽

W. Pfeiler

Keyword(s):

Long Range ◽

Heat Treatments ◽

Antiphase Boundaries ◽

Order And Disorder ◽

Initial States ◽

Isothermal Heat Treatments ◽

Long Range Ordering ◽

Kinetics Of

ABSTRACTL12-long-range ordering (LRO) was studied by residual resistometry in Cu3Au. Variations of LRO-parameter were produced by isochronal and isothermal heat treatments for different initial states of order. By comparison of order-order and disorder-order relaxations, the contributions to ordering of atomic jumps within ordered domains and of antiphase boundaries were separated. Analysing isothermal annealings yielded ordering energies of vacancies involved.

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Defect Recovery and Ordering in Ni3A1+B

MRS Proceedings ◽

10.1557/proc-364-309 ◽

1994 ◽

Vol 364 ◽

Cited By ~ 1

Author(s):

H. P. Karnthaler ◽

R. Kozubski ◽

W. Pfeiler ◽

C. Rentenberger

Keyword(s):

Temperature Regime ◽

Opposite Sign ◽

Antiphase Boundary ◽

Recovery Processes ◽

Dislocation Interactions ◽

Microhardness Testing ◽

Cold Rolled ◽

Defect Recovery ◽

Long Range Ordering ◽

Final Rolling

AbstractDefect recovery and long-range ordering (LRO) in Ni76Al24+0.19at.%B (400 wt.ppm) were studied by means of residual resistometry, TEM methods and microhardness testing. The material was cold-rolled with intermediate annealings and the samples were prepared from sheets exhibiting effective thickness reductions of 8 and 14%, respectively, achieved in the final rolling step.By TEM two recovery processes were observed. Firstly, superlattice intrinsic stacking faults (SISF) of large density recovered almost completely in the temperature regime between 443 and 700 K showing that they are bounded by dislocations of opposite sign. This indicates that most of the SISF are formed by pulling out dipoles and not by dislocation interactions as recently suggested. Secondly, the recovery of antiphase-boundary (APB) dissociated superlattice dislocations occurred by the annihilation of dipoles within the whole temperature regime leading finally to a loss of all dislocations at 1273 K.Despite some excess disorder caused by cold-rolling, the mechanical deformation did not influence qualitatively the LRO processes.

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The Ordered Phase Formation in Ti-Al-Ga Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069193 ◽

1970 ◽

Vol 28 ◽

pp. 440-441

Author(s):

Shiro Fujishiro ◽

Harold L. Gegel

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Titanium Alloys ◽

Growth Kinetics ◽

Stoichiometric Composition ◽

Good Potential ◽

Alpha Titanium ◽

Cold Rolled ◽

Kinetics Of ◽

Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

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