Publications related to Diffusionless transformation

Crystalline or amorphous? A critical evaluation of phenomenological phase selection rules

Johann Michler, Caroline Hain, Ashish Sharma

In this work, we reviewed the available phase selection rules comprising atomic size and topological aspects, entropies, enthalpies, melting points, valence and itinerant electron concentrations, as well as electronegativity, and validated them using a car ...

ELSEVIER SCI LTD2023

Room-temperature strength of the interfacial bond between silica inclusions and iron

Andreas Mortensen, Alejandra Inés Slagter, David Hernandez Escobar, Sergio Perosanz Amarillo

The strength of the interface between iron (Fe) and individual spherical silica (SiO2) inclusions of 5 +/- 1 mu m diameter is measured by means of in-situ micro-cantilever bending tests conducted under displacement control within a scanning electron micros ...

Pergamon-Elsevier Science Ltd2023

Effect of chromium content on microstructural evolution of CoNiAlW superalloy

Cyril Cayron

Effects of chromium (Cr) content on types and morphologies of various phases of a newly developed Co-Ni-Al-W superalloy (Co-30Ni-6W-9Al-3Ti-1Ta) have been investigated in this study. Microstructural examinations were carried out by field-emission scanning ...

SPRINGER HEIDELBERG2022

Non-Linear Behaviors In The Dynamics Of Complex Systems Through A Multifractal Hydrodynamic Model

Maria-Alexandra Paun

Some non-linear behaviors in the dynamics of complex systems using the Scale Relativity Theory in the form of Multifractal Hydrodynamic Model are analyzed. By assimilating any complex system to a mathematical multifractal-type object, it is shown that the ...

UNIV POLITEHNICA BUCHAREST, SCI BULL2022

Phase and microstructure selection in peritectic alloys under high G-V ratio

Wilfried Kurz, Stéphane Dobler

A new model for the case of a superposition of a phase transformation and a microstructure transition from columnar plane front to equiaxed dendritic growth for peritectic alloys is presented. This model is applied to Fe-Ni alloys where a phase transition ...

WALTER DE GRUYTER GMBH2022

Persistence of variant selection in red gold alloys

Roland Logé, Cyril Cayron, Margaux Nathalie Dominique Larcher

Recently, a new thermally activated distortion with amplification (TADA) effect has been reported in red gold alloys caused by the A1 -> L1(0) phase transformation. The macroscopic amplification is due to the persistence of variant selection nucleated unde ...

ELSEVIER SCIENCE SA2022

Phase transformation induced distortions in red gold alloys

Margaux Nathalie Dominique Larcher

Red gold alloys owe their warm and attractive colour to the combination of gold and copper atoms. Thanks to their good mechanical properties and resistance to corrosion, red gold alloys are used in luxury industries as well as in dentistry. Around the equi ...

EPFL2021

The effect of stress triaxiality on the phase transformation in transformation induced plasticity steels: Experimental investigation and modelling the transformation kinetics

Helena Van Swygenhoven, Nicola Casati, Efthymios Polatidis

In situ multiaxial loading during neutron diffraction tests were undertaken on a low-alloyed Quenched and Partitioning (Q&P) Transformation Induced Plasticity (TRIP) Bainitic Ferrite (TBF) steel with dispersed austenite particles. The effect of stress tria ...

2021

Characterization of untransformed ferrite in 10Cr and 12Cr ODS steels

Roland Logé

Two new ferrito-martensitic oxide dispersion strengthened (ODS) steels reinforced with (Y, Ti, O) nanoparticles were elaborated using a high-energy attritor. The milled powder was consolidated by hot extrusion at 1050 degrees C. The two types of ODS steels ...

ELSEVIER SCI LTD2021

Laser powder-bed fusion of metallic alloys with enhanced microstructures and properties

Navid Sohrabi

Laser powder-bed fusion (LPBF) is an additive manufacturing (AM) process that uses a laser to selectively melt a powder bed. This process can build dense samples with complicated geometries from a wide variety of metallic alloys. In this thesis, LPBF of al ...

EPFL2021

Understanding Thermomechanical Treatments Induced by Laser Powder Bed Fusion Process

Hossein Ghasemi Tabasi

Additive Manufacturing (AM) is referred to technologies that produce directly 3D parts in a layer-by-layer fashion. Laser Powder Bed Fusion (L-PBF) is one of the most important AM processes, enabling production of very complex metallic objects from a compu ...

EPFL2021

A critical assessment of experimental investigation of dynamic recrystallization of metallic materials

Roland Logé, Ke Huang

Dynamic recrystallization (DRX) often takes place during hot deformation of metallic materials, which then exerts significant influence on the final microstructures and mechanical properties of the formed components. A considerable number of published pape ...

2020

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

Measurement and prediction of the transformation strain that controls ductility and toughness in advanced steels

William Curtin, Helena Van Swygenhoven, Francesco Maresca, Efthymios Polatidis

New-generation multi-phase martensitic steels derive their high strength from the body-centered cubic (BCC) phase and high toughness from transformation of the metastable face-centered cubic (FCC) austenite that transforms into martensite upon loading. In ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Thermal coarsening of individual titanate nanowires and their assemblies: Surface vs. bulk diffusion

László Forró, Luca Rossi, Endre Horvath, Sergiy Katrych, Massimo Spina, Laurent Syavoch Bernard, Xavier Berdat

The thermal coarsening of titanate nanowires was investigated from room temperature to 1000 degrees C by AFM, SEM, XRD and Raman spectroscopy. Phase transformation kinetics and the external morphology were studied in two configurations: i) as individual an ...

2020

Deformation mechanisms in a superelastic NiTi alloy: An in-situ high resolution digital image correlation study

Helena Van Swygenhoven, Efthymios Polatidis

An in-situ high resolution digital image correlation investigation during uniaxial tensile deformation reveals the recoverable and the non-recoverable strain mechanisms in a Ni51Ti49 alloy with a mean grain size of 35 mu m. Recoverable strain is due to the ...

2020

Atomistic modeling of the solid-liquid interface of metals and alloys

Edoardo Baldi

Solidification is a phase transformation of utmost importance in material science, for it largely controls materials' microstructure on which a wide range of mechanical properties depends. Almost every human artifact undergoes a transformation that leads t ...

EPFL2020

Variant selection in martensitic steels

Annick Pauline Baur

The martensitic phase transformation in steel is one of the most famous solid state transformation because of its contribution in the development of the modern industry. This transformation from a face-centered cubic (FCC) high temperature phase, called th ...

EPFL2019

A crystallographic extension to the Olson-Cohen model for predicting strain path dependence of martensitic transformation

Helena Van Swygenhoven, Efthymios Polatidis

A modification to the empirical Olson-Cohen strain-induced austenite to martensite transformation kinetic model is proposed. The proposed kinetic model accounts for the stress state at the grain level and the crystallography of the transformation mechanism ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Deformation-induced martensitic transformation under multiaxial loading

Wei-Neng Hsu

The deformation-induced martensitic transformation observed in specific materials can enhance their mechanical properties or result in functional properties. For example, the transformation induced plasticity (TRIP) effect results in a good combination of ...

EPFL2019