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.

scholarly journals Crossover from Deformation Twinning to Lattice Dislocation Slip in Metal–Graphene Composites with Bimodal Structures

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 47
Author(s):  
Nikolai V. Skiba
Keyword(s):  
Plastic Deformation ◽  
Metal Matrix ◽  
Deformation Twinning ◽  
Lattice Dislocation ◽  
Dislocation Slip ◽  
Dislocation Emission ◽  
Bimodal Structure ◽  
Graphene Nanocomposite ◽  
Relaxation Channel ◽  
Micrometer Size

Theoretical model is suggested, which describes of a new micromechanism of crossover from deformation twinning to lattice dislocation slip in metal–graphene nanocomposite with a bimodal structure. In the framework of the model, the lattice dislocation slip occurs through emission of lattice dislocations from the disclinated grain boundary fragments between a nanocrystalline metal–matrix and large (micrometer-size) grains providing the plastic deformation of bimodal metal–graphene nanocomposite. It is shown that the lattice dislocation emission serves as an effective stress relaxation channel being in competition with nanocrack generation.

Microstructure Evolution of Near Gamma TiAl Intermetallic under Tensile Impact Loadings at High Temperatures

2010 ◽  
Vol 146-147 ◽  
pp. 1553-1556
Author(s):  
Yu Wang ◽  
Xiang Zan ◽  
Yue Hui He ◽  
Yang Wang
Keyword(s):  
Strain Rate ◽  
Microstructure Evolution ◽  
Deformation Mode ◽  
Deformation Twinning ◽  
Stacking Fault ◽  
Effect Of Temperature ◽  
Dislocation Slip ◽  
Tem Analysis ◽  
Dynamic Loadings ◽  
Deformation Modes

The effect of temperature and strain rate on the mechanical behavior and microstructure evolution of Near Gamma Ti-46.5Al-2Nb-2Cr (NG TiAl) was investigated at temperatures ranging from room temperatures to 840 under strain rates of 0.001, 320, 800 and 1350s-1. The TEM analysis indicated that deformation twinning and stacking fault are the main deformation modes under dynamic loadings and dislocation slip is another important deformation mode under quasi-static loadings. The density of deformation twinning and/or stacking fault increases with the increased temperature and strain rate.

Polarization of plastic deformation modes in polysynthetically twinned TiAl crystals

2003 ◽  
Vol 18 (3) ◽  
pp. 702-708 ◽  
Author(s):  
V. Paidar ◽  
K. Kishida ◽  
M. Yamaguchi
Keyword(s):  
Plastic Deformation ◽  
Deformation Mode ◽  
Deformation Twinning ◽  
Additional Stress ◽  
Burgers Vector ◽  
Stress Increase ◽  
Loading Direction ◽  
Deformation Modes ◽  
Lamellar Interfaces

Polarization of deformation twinning (its propagation in a certain sense but not in the opposite one) is taken for granted. However, the same phenomenon can occur for a superdislocation glide as well, as is demonstrated in this paper. The consequences for plastic deformation of polysynthetically twinned TiAl crystals with the lamellar interfaces parallel to the loading direction are discussed. It is not the interface itself that is an obstacle for propagating deformation but also the fact that a deformation mode with the parallel Burgers vector cannot be activated in the neighboring lamella due to the directionality of superdislocation motion leading to additional stress increase.

On the Formability and Microstructural Characteristics of AISI 301 Parts Formed by Single-Point Incremental Forming

2011 ◽  
Vol 473 ◽  
pp. 869-874 ◽  
Author(s):  
Ivan Lonardelli ◽  
Paolo Bosetti ◽  
Stefania Bruschi ◽  
Alberto Molinari
Keyword(s):  
Incremental Forming ◽  
Early Stage ◽  
Single Point ◽  
Deformation Mode ◽  
Xrd Analysis ◽  
Deformation Twinning ◽  
Dislocation Slip ◽  
Material Object ◽  
Single Point Incremental Forming ◽  
Tem Analysis

The present work focuses on the correlation between the material tendency to be deformed by incremental sheet forming and the microstructural features that appear during the process itself. The material object of the study is the stainless steel AISI 301L. Single-point incremental forming (SPIF) experiments were carried out and the material formability evaluated. X ray diffraction (XRD) analysis was utilized to determine the fraction of transformed martensite along the wall of formed parts at different levels of thickness reduction. TEM analysis was then employed to analyze the microstructure developed during the SPIF process. Two fundamental deformation mechanisms are observed, which could explain the remarkable material formability achievable during the SPIF process: strain induced martensitic transformation, and deformation twinning. Particularly, deformation twinning (instead of dislocation slip) appears to be the preferred plastic deformation mode of austenite at the early stage of the process, leading to the formation of multiple nano-twins in coarse grains that are responsible for the material ductility enhancement.

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.

The Role of Texture, Temperature and Strain Rate in the Activity of Deformation Twinning

2005 ◽  
Vol 495-497 ◽  
pp. 1037-1042 ◽  
Author(s):  
Donald W. Brown ◽  
Sean R. Agnew ◽  
S.P. Abeln ◽  
W.R. Blumenthal ◽  
Mark A.M. Bourke ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Deformation Mode ◽  
Relative Activity ◽  
Deformation Twinning ◽  
Underlying Structure ◽  
Cubic Metals ◽  
Pyramidal Slip ◽  
Crystallographic Symmetry

Plastic deformation in cubic metals is relatively simple due to the high crystallographic symmetry of the underlying structure. Typically, one unique slip mode can provide arbitrary deformation. This is not true in lower symmetry hexagonal metals, where prismatic and basal slip (the usual favored modes) are insufficient to provide arbitrary deformation. Often, either pyramidal slip and/or deformation twinning must be activated to accommodate imposed plastic deformation. The varied difficulty of activating each of these deformation mechanisms results in a highly anisotropic yield surface and subsequent mechanical properties. Further, the relative activity of each deformation mode may be manipulated through control of the initial crystallographic texture, opening new opportunities for the optimization of mechanical properties for a given application.

scholarly journals Deformation Twinning Induced High Tensile Ductility of a Gradient Nanograined Cu-Based Alloy

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2451
Author(s):  
Junjie Wang ◽  
Nairong Tao
Keyword(s):  
Plastic Deformation ◽  
Tensile Properties ◽  
Deformation Mechanism ◽  
Tensile Ductility ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Deformation Twinning ◽  
Mechanical Twinning

We investigated the tensile properties of gradient nanograined Cu and CuAl samples prepared by plastic deformation. Tensile tests showed that the gradient nanograined Cu-4.5Al sample exhibits a uniform elongation of ~22% without any cracks, while the uniform elongation of the gradient nanograined Cu sample is only ~18%. Numerous mechanical twinning retards the softening of the nanograins and accommodates a high tensile ductility in the gradient nanograined Cu-4.5Al sample. This work indicates that mechanical twinning is a potential deformation mechanism to achieve high tensile ductility of nanograined materials.

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.

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