Defect Recovery and Ordering in Ni3A1+B

1994 ◽  
Vol 364 ◽  
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.

Untersuchung atomarer Fehlstellen in verformtem und abgeschrecktem Nickel

1962 ◽  
Vol 17 (3) ◽  
pp. 228-235 ◽  
Author(s):  
Dieter Schumacher ◽  
Wolfgang Schule ◽  
Alfred Seeger
Keyword(s):  
Room Temperature ◽  
Cold Work ◽  
Stage Iv ◽  
Stage Iii ◽  
Polycrystalline Nickel ◽  
Volume Increase ◽  
Recovery Processes ◽  
Free Interstitial ◽  
Cold Rolled ◽  
Energy Of Formation

Polycrystalline nickel (purity 99.9% was either cold-rolled below room temperature or quenched from 1000 °C. The recovery of the electrical resistivity was studied between 0 °C °C and 300 °C. After cold-work two separate recovery processes were found in this temperature range (stage III near 80 °C. stage IV near 250 °C with activation energies of 1.09 ± 0.05 ev and 1.55 ± 0.10 ev. respectively.After quenching from 1000 °C only stage IV was present (maximum of the recovery rate near 270 °C, activation energy about 1.5 ev), whereas stage III was not observed. On account of the present results and other available data free interstitial migration is attributed to stage III and the migration of single vacancies to stage IV. We estimate that the energy of formation of single vacancies in nickel is 1.3 — 1.4 ev, and that the volume increase per vacancy is 0.82 atomic volumes.

Evolution of Microstructure and Mechanical Properties during Annealing of Cold Rolled Fe-24Mn-3Al-2Si-1Ni-0.06C Twip Steel

2011 ◽  
Vol 409 ◽  
pp. 719-724 ◽  
Author(s):  
Ahmed A. Saleh ◽  
Azdiar A. Gazder ◽  
Dagoberto Brandao Santos ◽  
Elena V. Pereloma
Keyword(s):  
Twip Steel ◽  
Uniaxial Tensile ◽  
Automotive Applications ◽  
Uniaxial Tensile Testing ◽  
Annealing Twins ◽  
Back Scattering ◽  
Microhardness Testing ◽  
Twip Steels ◽  
Cold Rolled ◽  
Evolution Of Microstructure

TWinning Induced Plasticity (TWIP) steels have been recently developed as a promising material for automotive applications. In the present work the recrystallisation behaviour of 42% cold-rolled Fe-24Mn-3Al-2Si-1Ni-0.06C TWIP steel was investigated during isochronal annealing for 300s via microhardness testing, Electron Back-Scattering Diffraction (EBSD) and uniaxial tensile testing. EBSD internal misorientation data corroborates recrystallised fraction estimates from microhardness measurements. Annealing twins play an important role during recrystallisation by bulging at the deformed grain boundaries during nucleation and generating twin related orientations. During uniaxial tension, the recovered condition recorded three work hardening regions while all partially recrystallised samples exhibited four regions. A modified Hollomon scheme is suggested to account for the effect of strain on microstructure refinement.

scholarly journals IMPACT OF COLD PLASTIC DEFORMATION AND THERMAL POST-TREATMENT ON THE PHYSICAL PROPERTIES OF COPPER BASED ALLOYS Al-BRONZE AND α-BRASS

2021 ◽  
Vol 27 (3) ◽  
pp. 114-121
Author(s):  
Samiul Kaiser ◽  
Mohammad Salim Kaiser
Keyword(s):  
Pure Copper ◽  
Rolling Direction ◽  
Optical Microscope ◽  
Solid Solution Hardening ◽  
Aged Alloy ◽  
Cold Plastic Deformation ◽  
Scanning Calorimetry ◽  
Stress Relieving ◽  
Microhardness Testing ◽  
Cold Rolled

The copper based alloys Al-bronze and α-brass containing each of 10wt% aluminum and zinc were prepared by casting. Afterwards, the specimens were cold-rolled with various percentages of deformation and the cold-rolled samples were aged subsequently at the varied time for four hours and temperatures ranging up to 500°C. Samples underwent characterizations by microhardness testing, electrical resistivity, optical properties, differential scanning calorimetry as well as microstructure analysis using an optical microscope. The results showed that the hardening of Cu-based alloys was taken place due to solid-solution hardening. Al addition accelerated the hardness through ageing due to the formation of various intermetallic copper aluminites into the aged alloy which was hard and brittle in nature. The resistivity decreased marginally through heat treatment due to the stage of stress relieving, recovery, precipitation coarsening as well as recrystallization and increased for arranging different intermetallics into the alloys. The microstructural study revealed that the cold rolled alloys content the different phases of elongated grain at the rolling direction. Meanwhile higher ageing temperatures at 500°C for one hour led to recrystallization and grain growth especially in pure copper and Cu-10Zn alloys.

Strain-Induced Ferromagnetism in Fe-40Al Single Crystals

2000 ◽  
Vol 646 ◽  
Author(s):  
D. Wu ◽  
I. Baker
Keyword(s):  
Magnetic Susceptibility ◽  
Phase Boundary ◽  
Saturation Magnetization ◽  
Single Crystals ◽  
Crystal Orientation ◽  
Antiphase Boundary ◽  
Degree Of Deformation ◽  
Calorimetric Measurements ◽  
Cold Rolled ◽  
Anti Phase Boundary

ABSTRACTRecent research [1–3] suggests that strain-induced ferromagnetism in lightly-strained FeAl arises chiefly from anti-phase boundary tubes. Magnetic and calorimetric measurements have been performed on two different orientations of B2-structured Fe-40Al single crystals that had been cold rolled to a variety of strains. The saturation magnetization and magnetic susceptibility are related to the enthalpy associated with the annealing out of antiphase boundary tubes and, hence, to the degree of deformation and crystal orientation.

scholarly journals TEM Study of Nanoprecipitation and Dislocation Interactions in Novel Cold Rolled "Nano-Steel"

2021 ◽  
Vol 27 (S1) ◽  
pp. 3410-3411
Author(s):  
Angelos Kaldellis ◽  
Nikolaos Makris ◽  
Petros Tsakiridis ◽  
George Fourlaris
Keyword(s):  
Dislocation Interactions ◽  
Cold Rolled

Solid State Reaction Mechanism and Microstructure Evolution of Ni-Al Powders during High Energy Ball Milling Revisited by TEM

2015 ◽  
Vol 21 (4) ◽  
pp. 953-960 ◽  
Author(s):  
Guohua Fan ◽  
Lin Geng ◽  
Yicheng Feng ◽  
Xiping Cui ◽  
Xudong Yan
Keyword(s):  
Electron Microscopy ◽  
Ball Milling ◽  
Microstructure Evolution ◽  
Exothermic Reaction ◽  
Antiphase Boundary ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Diffusion Reaction ◽  
Energy Ball ◽  
Long Range Ordering

AbstractMicrostructure evolution during the formation of B2–NiAl by high energy ball milling of equiatomic elemental mixtures was studied by X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy (TEM). The crystallite size, lattice defects and ordering of the B2–NiAl were monitored via TEM as function of milling time. The diffusion reaction, Ni+Al→NiAl3 or/and Ni2Al3, occurred during high energy ball milling, and to a certain extent offered the stored energy for the explosive exothermic reaction, Ni+Al→B2–NiAl. The fine microstructure of newly formed B2–NiAl after 5 h milling involved high density defects, e.g. antiphase boundary, long range ordering domains, vacancies, and dislocations.

Symbiotic Stars at Optical, Infrared and Radio Wavelengths

1979 ◽  
Vol 46 ◽  
pp. 125-149 ◽  
Author(s):  
David A. Allen
Keyword(s):  
Temperature Regime ◽  
Type Star ◽  
Stellar Systems ◽  
Symbiotic Stars ◽  
Lower Excitation ◽  
Definition Of ◽  
Original Type

No paper of this nature should begin without a definition of symbiotic stars. It was Paul Merrill who, borrowing on his botanical background, coined the termsymbioticto describe apparently single stellar systems which combine the TiO absorption of M giants (temperature regime ≲ 3500 K) with He II emission (temperature regime ≳ 100,000 K). He and Milton Humason had in 1932 first drawn attention to three such stars: AX Per, CI Cyg and RW Hya. At the conclusion of the Mount Wilson Ha emission survey nearly a dozen had been identified, and Z And had become their type star. The numbers slowly grew, as much because the definition widened to include lower-excitation specimens as because new examples of the original type were found. In 1970 Wackerling listed 30; this was the last compendium of symbiotic stars published.

Observation of Superlattice Dislocations on Cube Planes in Ni3Al

1973 ◽  
Vol 31 ◽  
pp. 174-175 ◽  
Author(s):  
J. M. Oblak ◽  
W. H. Rand
Keyword(s):  
Nearest Neighbor ◽  
Antiphase Boundary ◽  
Nearest Neighbors ◽  
High Energy ◽  
Cross Slip ◽  
Octahedral Plane ◽  
Trapping Mechanism ◽  
Slip Traces

The energy of an a/2 <110> shear antiphase. boundary in the Ll2 expected to be at a minimum on {100} cube planes because here strue ture is there is no violation of nearest-neighbor order. The latter however does involve the disruption of second nearest neighbors. It has been suggested that cross slip of paired a/2 <110> dislocations from octahedral onto cube planes is an important dislocation trapping mechanism in Ni3Al; furthermore, slip traces consistent with cube slip are observed above 920°K.Due to the high energy of the {111} antiphase boundary (> 200 mJ/m2), paired a/2 <110> dislocations are tightly constricted on the octahedral plane and cannot be individually resolved.

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