Publications related to Twin | EPFL Graph Search

EBSD study of variant reorientation, texture, and twin formation in a martensitic NiTi alloy deformed in compression

Cyril Cayron, Roland Logé, Mathijs Pieter van der Meer, Junfeng Xiao

Martensitic crystallography plays a vital role in the texture evolution and mechanical properties in Nickel-Titanium (NiTi) shape memory alloys when subjected to deformation. However, their microstructural changes during deformation are not well known and ...

Pergamon-Elsevier Science Ltd2023

The concept of axial weak twins

Cyril Cayron

It is generally assumed that the parent-twin interface is a fully invariant plane. The calculations of the rational interfaces of the type I twins and irrational interfaces of the type II twins are based on this hypothesis. Recently, some asymmetric facets ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Complements to Mugge and Friedel's Theory of Twinning

Cyril Cayron

The crystallography of twinning is based on the concepts of simple shear and obliquity introduced by Mugge, Mallard and Friedel at the turn of the last century, with tensor mathematics later developed by Bilby, Bevis and Crocker in the 1960s. We propose a ...

2020

Diffraction artefacts from twins and stacking faults, and the mirage of hexagonal, polytypes or other superstructures

Cyril Cayron

Recently, a hexagonal phase has been reported in high carbon steels in several studies. Here, we show that the electron microscopy results used in these studies were erroneously interpreted. The extra-spots in the diffraction patterns and the odd contrasts ...

2020

Automated Platform for Long-Term Culture and High-Content Phenotyping of Single C. elegans Worms

Johan Auwerx, Martinus Gijs, Matteo Cornaglia, Laurent Mouchiroud, Rongrong Xiang, Elena Katsyuba, Hüseyin Baris Atakan

The nematode Caenorhabditis elegans is a suitable model organism in drug screening. Traditionally worms are grown on agar plates, posing many challenges for long-term culture and phenotyping of animals under identical conditions. Microfluidics allows for ' ...

Nature Research2019

The mechanics of crack-tip dislocation emission and twinning

Predrag Andric

Dislocation emission from a crack tip is a necessary mechanism for crack tip blunting and toughening. A material is intrinsically ductile under Mode I loading when the critical stress intensity

K_{Ie}

for dislocation emission is lower than the critical s ...

EPFL2019

A one-step mechanism for new twinning modes in magnesium and titanium alloys modelled by the obliquity correction of a (58 degrees, a+2b) prototype stretch twin

Cyril Cayron

The {11-22} and {11-26} twinning modes were recently discovered by Ostapovets et al. [Philos. Mag. (2017), 97, 1088-1101] and interpreted as {10-12}-{10-12} double twins formed by the simultaneous action of two twinning shears. Another interpretation is pr ...

Int Union Crystallography2018

Fighting preterm birth with novel surgical tools and biomaterials engineering

Yannick Robert Devaud

With advances in fetal diagnosis and therapy, fetoscopy has become a good option to treat a series of life threatening diseases like twin-to-twin transfusion syndrome or severe congenital diaphragmatic hernia. The efficacy of fetoscopy for those types of d ...

EPFL2017

Hard-sphere displacive model of extension twinning in magnesium

Cyril Cayron

A crystallographic displacive model is proposed for the extension twins in magnesium. The atomic displacements are established, and the homogeneous lattice distortion is analytically expressed as a continuous angular-distortive matrix that becomes a shear ...

Elsevier Sci Ltd2017

Embrittlement induced by the synergistic effects of radiation damage and helium in structural steels

Kun Wang

Ferritic/martensitic steels are candidate materials for fusion reactor structural components, liquid metal containers of spallation neutron sources, and accelerator driven systems, with good radiation resistance and thermo-mechanical properties. However, e ...

EPFL2015

A New Mechanism for Twin Growth in Mg Alloys

William Curtin, Aitor Luque Gomez, Maryam Ghazisaeidi

Twinning is an important deformation mode in lightweight Mg alloys, but the mechanisms of nucleation and growth of twins and their interactions with solutes remain largely unresolved. Here, a new model for thermally-activated, stress-driven growth of twin ...

Elsevier2014

Microstructure and precipitates in annealed Co38Ni33Al29 ferromagnetic shape memory alloy

Barbora Bártová

Transmission electron microscopy was performed to investigate the microstructure and precipitates in the annealed Co38Ni33Al29 ferromagnetic shape memory alloy. Apart from the dendritic secondary phase in the austenite matrix, micron-sized (up to 100 μm) f ...

Elsevier Science Sa2013

Morphology and Growth Kinetic Advantage of Quenched Twinned Dendrites in Al-Zn Alloys

Michel Rappaz, André Phillion, Mario Alberto Salgado Ordorica

Twinned dendrites appearing in an Al-26 wt pct Zn alloy have been quenched during growth using a specifically designed setup that is positioned on top of a directional solidification experiment. X-ray tomography performed at the Swiss Light Source (SLS-bea ...

Springer Verlag2013

Deformation modes in magnesium (0001) and (0 1 -1 1) single crystals: simulations versus experiments

William Curtin, Aitor Luque Gomez, Maryam Ghazisaeidi

Magnesium is an excellent candidate as lightweight structural material, but has strong plastic anisotropy, and the activation of, operation of, and competition between different slip and twinning systems remain active areas of research. Here, the nucleatio ...

Institute of Physics2013

HREM studies of twins in Cd1−xZnxTe (x ≈ 0.04) thin films grown by molecular beam epitaxy

Nava Setter, Marco Cantoni, Igor Stolichnov

The microstructure of ferroelectric Cd1−xZnxTe (CZT) thin films with x ≈ 0.04 grown by molecular beam epitaxy has been studied by means of cross sectional high-resolution transmission electron microscopy (HREM). High- density {1 1 1} lamellar twins are fou ...

2009

Study of twinned dendrite growth stability

Michel Rappaz, Jonas Valloton, Mario Alberto Salgado Ordorica

Under certain thermal conditions (G approximate to 1 x 10(4) K/m, v(s) approximate to 1 x 10(-3) m/s), < 1 1 0 > twinned dendrites appear in aluminum alloys and can overgrow regular columnar dendrites, provided that some convection is also present in the m ...

Elsevier2009

Characterization and modeling of twinned dendrite growth

Mario Alberto Salgado Ordorica

The formation of feathery grains during semi-continuous casting of Al-alloys [1, 2] is an interesting problem from both practical and theoretical points of view. These structures are formed by a lamellar sequence of twinned and untwinned regions separated ...

EPFL2009

Quantitative Morphometrical Characterization of Human Pronuclear Zygotes

Michaël Unser, Philippe Thévenaz

BACKGROUND: Identification of embryos with high implantation potential remains a challenge in in vitro fertilization (IVF). Subjective pronuclear (PN) zygote scoring systems have been developed for that purpose. The aim of this work was to provide a softwa ...

Oxford University Press2008