Mechanical twinning of Cu-1Wt pct be at room temperature

1970 ◽  
Vol 1 (5) ◽  
pp. 1483-1485 ◽  
Author(s):  
B. C. Wonsiewicz ◽  
T. C. Tisone ◽  
G. Y. Chin
Keyword(s):  
Room Temperature ◽  
Mechanical Twinning

Mechanical Twinning of Titanium Single Crystals

1970 ◽  
Vol 28 ◽  
pp. 454-455 ◽  
Author(s):  
S. Fujishiro ◽  
J. W. Edington
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Mechanical Twinning ◽  
Compression Tests ◽  
Compression Axis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Schmid Factor ◽  
Twinning System ◽  
Crystallographic Orientations

Compression tests were performed on titanium single crystals at room temperature and at −196°C, and the twinning mode was investigated using metallographic, electron microscopy and X-ray diffraction studies. Four crystallographic orientations, each different with respect to the compression axis, were selected in order to make the prospective twinning system planes, , , and , subject to a maximum resolved shear stress, i.e., Schmid factor = 0. 5. type twins were the most frequently observed in all the crystals tested and type twins were the second most frequent.

Atomic-Scale Design for Enhanced Low Temperature Twinning in ZrCr2-Based Laves Phases

1999 ◽  
Vol 578 ◽  
Author(s):  
W.-Y. Kim ◽  
D.E. Luzzi
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
Alloy System ◽  
Deformation Mode ◽  
Systematic Investigation ◽  
Mechanical Twinning ◽  
Atomic Scale ◽  
Laves Phases ◽  
Drastic Effect ◽  
Scale Design

AbstractRecently, we have designed and produced several transition metal Laves phases with low-temperature compressive ductility. These improved alloys demonstrate that manipulation of atomic-scale structure can have a drastic effect on meso-scale deformation behavior. To gain a basic understanding of the role of atomic-scale substitutions on the room temperature mechanical properties, a systematic investigation of the Laves ZrCr2-based alloy system alloyed with Hf, Nb, Ta and Ti was conducted and is reported here. Extensive room temperature ductility was obtained in the Hf-alloyed ternary Laves phase alloy system. Mechanical twinning is found to be the predominant deformation mode at room temperature in this alloy system. It is emphasized that Hf substitution in the Zr sublattice of ZrCr2 may play the most prominent role in changing the local electronic structure resulting in easier twinning.

Deformation Twinning, Slip, Martensite Formation and Crack Inhibition in the B2-Type Zr50Pd35Ru15 Alloy

1991 ◽  
Vol 246 ◽  
Author(s):  
R.M. Waterstrat ◽  
L.A. Bendersky ◽  
R. Kuentzler
Keyword(s):  
Crystal Structure ◽  
Plastic Deformation ◽  
Room Temperature ◽  
Deformation Mode ◽  
Deformation Twinning ◽  
Mechanical Twinning ◽  
Dislocation Slip ◽  
Slip Mode ◽  
Martensite Formation ◽  
Additional Mode

AbstractEnhanced room temperature toughness of the Zr50Pd35Ru15B2 phase alloy was found to be a result of the activation of an additional deformation mode besides the b=[001] dislocation slip mode - {114}-type mechanical twinning. The twinning is a true one, i.e. there is no change in the ordered crystal structure. Another additional mode of plastic deformation, expected for more Pd rich alloys, is the formation of stress-induced martensite. The martensite was found to have a CrBtype structure.

Interactions of Mechanical Twinning and Dislocation Glide with Polytwin-Interfaces in L1o-Ordered Iron-Palladium Intermetallics

2002 ◽  
Vol 753 ◽  
Author(s):  
Huiping Xu ◽  
Jörg Wiezorek
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Mechanical Twinning ◽  
Temperature Deformation ◽  
Defect Structures ◽  
Shear Transfer ◽  
Dislocation Glide ◽  
Transmission Electron ◽  
Mechanical Twins

ABSTRACTThe defect structures in polytwinned (PT) FePd have been studied after room temperature deformation by transmission electron microscopy (TEM). Interactions between gliding dislocations and mechanical twins with the {101}-conjugated PT-interfaces have been identified. Based on crystallographic analyses of shear transfer of dislocations and microtwins across the PT-interfaces in FePd boundary reactions have been identified that are consisted with the TEM observations. A model has been proposed, which is suitable to rationalize significant contributions to strain-hardening from these defect-interface interactions in PT-FePd.

scholarly journals A Dislocation-scale Characterization of the Evolution of Deformation Microstructures around Nanoindentation Imprints in a TiAl Alloy

2018 ◽  
Author(s):  
Antoine Guitton ◽  
Hana Kriaa ◽  
Emmanuel Bouzy ◽  
Julien Guyon ◽  
Nabila Maloufi
Keyword(s):  
Plastic Deformation ◽  
Room Temperature ◽  
Tial Alloy ◽  
Mechanical Twinning ◽  
Contrast Imaging ◽  
Electron Channeling ◽  
The Poor ◽  
Before And After ◽  
Scale Characterization

In this work, plastic deformation was locally introduced at room temperature by nanoindentation on a γ-TiAl based alloy. Comprehensive analyzes of microstructures were performed before and after deformation. In particular, the Burgers vectors, the line directions and the mechanical twinning systems were studied via accurate electron channeling contrast imaging. Accommodation of the deformation are reported and a scenario is proposed. All features help to explain the poor ductility of the TiAl based alloys at room temperature.

scholarly journals A Dislocation-Scale Characterization of the Evolution of Deformation Microstructures around Nanoindentation Imprints in a TiAl alloy

2018 ◽  
Author(s):  
Antoine Guitton ◽  
Hana Kriaa ◽  
Emmanuel Bouzy ◽  
Julien Guyon ◽  
Nabila Maloufi
Keyword(s):  
Plastic Deformation ◽  
Room Temperature ◽  
Tial Alloy ◽  
Mechanical Twinning ◽  
Contrast Imaging ◽  
Electron Channeling ◽  
The Poor ◽  
Before And After ◽  
Scale Characterization

In this work, plastic deformation was locally introduced at room temperature by nanoindentation on a γ-TiAl based alloy. Comprehensive analyzes of microstructures were performed before and after deformation. In particular, the Burgers vectors, the line directions and the mechanical twinning systems were studied via accurate electron channeling contrast imaging. Accommodation of the deformation are reported and a scenario is proposed. All features help to explain the poor ductility of the TiAl based alloys at room temperature.

THE EFFECT OF SOLUTE ON SLIP AND MECHANICAL TWINNING IN IRON ALLOYS

1967 ◽  
Vol 45 (2) ◽  
pp. 541-557 ◽  
Author(s):  
G. F. Bolling ◽  
R. H. Richman
Keyword(s):  
Room Temperature ◽  
Deformation Mode ◽  
Solute Concentration ◽  
Mechanical Twinning ◽  
Extensive Study ◽  
Liquid Distribution ◽  
Initial Flow ◽  
Nucleation Mechanisms ◽  
Dislocation Behavior ◽  
Mechanical Twins

The effects of solute type and concentration upon the nature of, and stresses for, plastic flow in polycrystalline iron solid solutions have been examined. An extensive study was made using Al, Be, Ge, P, Si, and Sn; limited examples with Co, Sb, and Ti are also included. Three experimental observations stand out: (i) At room temperature and lower solute concentration the flow stress for slip increases monotonically with the parameter c|ln km|. Here c is the solute concentration, and the solid–liquid distribution coefficient, km, differentiates the solute type, (ii) At room temperature, there is a transition in the deformation mode from slip to twinning at a concentration that decreases with increasing |ln km|. The actual stresses for mechanical twinning can be compared with those at 77 °K; they are higher and provide a second measure for the deformation-mode transition, (iii) At 77 °K the initial deformation mode is predominantly mechanical twinning, and, below concentrations producing atomic ordering, the initial flow stresses are independent of solute concentration and type.When these observations are accompanied by tests for the propagation-controlled phenomenon of continual mechanical twinning, we deduce the following: (i) and (ii) show that solute promotes mechanical twinning as a consequence of its effect on dislocation behavior, most likely by requiring fast-moving individual dislocations, while (iii) shows that a threshold stress exists for the nucleation of mechanical twins that cannot easily be explained by existing twin-nucleation mechanisms.

The Correlation between Stacking Fault Energy and the Work Hardening Behaviour of High-Mn Twinning Induced Plasticity Steel Tested at Various Temperatures

2014 ◽  
Vol 922 ◽  
pp. 676-681 ◽  
Author(s):  
Vadim Shterner ◽  
Ilana B. Timokhina ◽  
Hossein Beladi
Keyword(s):  
Mechanical Properties ◽  
Work Hardening ◽  
Room Temperature ◽  
True Strain ◽  
Testing Machine ◽  
Mechanical Twinning ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Tensile Testing Machine ◽  
Twip Steels

High-Mn Twinning Induced Plasticity (TWIP) steels have superior mechanical properties, which make them promising materials in automotive industry to improve the passenger safety and the fuel consumption. The TWIP steels are characterized by high work hardening rates due to continuous mechanical twin formation during the deformation. Mechanical twinning is a unique deformation mode, which is highly governed by the stacking fault energy (SFE). The composition of steel alloy was Fe-18Mn-0.6C-1Al (wt.%) with SFE of about 25-30 mJ/m2at room temperature. The SFE ensures the mechanical twinning to be the main deformation mechanism at room temperature. The microstructure, mechanical properties, work hardening behaviour and SFE of the steel was studied at the temperature range of ambient≤T[°C]≤400°C. The mechanical properties were determined using Instron tensile testing machine with 30kN load cell and strain rate of 10-3s-1and the work hardening behaviour curves were generated using true stress and true strain data. The microstructure after deformation at different temperatures was examined using Zeiss Supra 55VP SEM. It was found that an increase in the deformation temperature raised the SFE resulting in the deterioration of the mechanical twinning that led to decrease not only in the strength but also in the total strain of the steel. A correlation between the temperature, the SFE, the mechanical twinning, the mechanical properties and the work hardening rate was also found.

Mechanical twinning and subgrain formation in ordered Ti50Ni47Fe3

1988 ◽  
Vol 46 ◽  
pp. 618-619
Author(s):  
W. J. Moberly
Keyword(s):  
Mechanical Properties ◽  
Martensitic Transformation ◽  
Room Temperature ◽  
Cold Working ◽  
Thermomechanical Processing ◽  
Mechanical Twinning ◽  
Deformation Mechanisms ◽  
Tini Alloy ◽  
Recovery Annealing ◽  
Subgrain Formation

TiNi is an intermetallic compound with the B2(CsCl) crystal structure. As temperature decreases, it undergoes a martensitic transformation from cubic B2 to monoclinic B19', the reversibility of which is responsible for shape memory properties. Ordered intermetallics generally have limited ductilty, however, >50% elongation of TiNi has been produced by either warm or cold working. Consequently, thermomechanical processing has resulted in improved mechanical properties. TEM is required to characterize the deformation mechanisms (mechanical twinning and slip) and resulting substructures.Substitution of 3%Fe for Ni into the binary TiNi alloy (Ti50Ni47Fe3) depresses the martensitic transformation, such that room temperature working does not stress induce the martensitic transformation. In order to improve the mechanical properties of this B2 intermetallic, fully annealed (875°C/2 hrs) bars have been cold swaged 10%,20%,30% and 40%, followed by different recovery annealing treatments. Additional samples have been warm swaged at 500°C. The structure is observed optically and by TEM, utilizing Philips' EM 400 twin and EM 430 super twin microscopes.

On mechanical twinning in iridium under compression at room temperature

1994 ◽  
Vol 13 (12) ◽  
pp. 865-867 ◽  
Author(s):  
R. Adamesku ◽  
S. Grebenkin ◽  
A. Yermakov ◽  
P. Panfilov
Keyword(s):  
Room Temperature ◽  
Mechanical Twinning
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