Publications associées à Molecular dynamics simulations of phase formation and stability in the Al(Ni) system under irradiation

Machine learning for metallurgy IV: A neural network potential for Al-Cu-Mg and Al-Cu-Mg-Zn

William Curtin, Daniel John Gilles Marchand

Most metallurgical properties, e.g., dislocation propagation, precipitate formation, can only be fully understood atomistically but most phenomena and quantities of interest cannot be measured experimentally. Accurate simulation methods are essential but f ...

2022

Neural Network Potentials for Age Hardening Aluminum Alloys

Daniel John Gilles Marchand

High-strength metal alloys achieve their performance via careful control of precipitates and solutes. The nucleation, growth, and kinetics of precipitation, and the resulting mechanical properties, are inherently atomic scale phenomena, particularly during ...

EPFL2022

Processability, microstructure and precipitation of a Zr-modified 2618 aluminium alloy fabricated by laser powder bed fusion

Christian Leinenbach, Xavier Maeder

Additive manufacturing offers the opportunity to produce complex geometries from novel alloys with improved properties. Adapting conventional alloys to the process-specific properties can facilitate rapid implementation of these materials in industrial pra ...

2022

Development of High-Strength Aluminum Alloys for Additive Manufacturing

Marvin Lennard Schuster

Metal additive manufacturing (AM) offers the possibility to rapidly produce complex geometries that are not achievable with conventional manufacturing methods. The two most common technologies, Laser Powder Bed Fusion (LPBF) and Direct Metal Deposition (DM ...

EPFL2022

Modeling of precipitate strengthening with near-chemical accuracy: case study of Al-6xxx alloys

William Curtin, Yi Hu

Many metal alloys are strengthened by controlling precipitation to achieve an optimal peak-aged condi-tion where the strength-limiting processes of precipitate shearing and Orowan looping are thought to be comparable. Qualitative models have long captured ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Catalyzing Bond-Dissociation in Graphene via Alkali-Iodide Molecules

Klaus Kern, Stephan Rauschenbach, Sabine Abb, Sven Alexander Szilagyi, Hannah Julia Ochner

Atomic design of a 2D-material such as graphene can be substantially influenced by etching, deliberately induced in a transmission electron microscope. It is achieved primarily by overcoming the threshold energy for defect formation by controlling the kine ...

WILEY-V C H VERLAG GMBH2021

Precipitation Strengthening in Al-Mg-Si Alloys

Yi Hu

Precipitation strengthening is one of the key strengthening strategies in many industrial alloys like aluminum alloys, nickel-based superalloys, etc. The yield strength of alloy is improved by forming precipitates in materials and employing them as obstacl ...

EPFL2021

Concurrent multiscale modeling and theory of solute-strengthening for dilute and complex concentrated alloys

Shankha Nag

Under common processing conditions, both dilute and complex concentrated alloys are often realized as random alloys, with no correlation in the occupancy of lattice sites by the constituent atom types. The current thesis primary addresses two problems in r ...

EPFL2020

Solidification of Metallic Alloys: Does the Structure of the Liquid Matter?

Michel Rappaz, Güven Kurtuldu

In 1952, Frank (Proc R Soc Lond Ser-Math Phys Sci 215:43-46, 1952) already postulated that Icosahedral Short Range Order (ISRO) of atoms in the liquid could possibly explain the large nucleation undercoolings measured in metallic alloys by Turnbull and Fis ...

SPRINGER2020

Charge transfer dynamics in Ar+ + CO

Eduardo Carrascosa Casado

Differential cross sections for the charge transfer reaction between Ar(+)and CO have been measured using three-dimensional velocity map imaging in a crossed beam setup at the two relative collision energies 0.55 and 0.74 eV. We find dominant forward scatt ...

Taylor & Francis2020

Atomic Scale Investigations into the Origins of Ductility in Mg Alloys

Rasool Ahmad

The industrial applications of Mg, the lightest structural metal, and abundant in Earth's crust, are hampered by its low intrinsic ductility and low fracture toughness at room temperature which is attributed to the underlying less symmetric and plastically ...

EPFL2020

Influence of Minor Cr-Additions to the Growth of Columnar Dendrites in Al-Zn Alloys: Influence of Icosahedral Short Range Order in the Liquid

Michel Rappaz, Güven Kurtuldu

The effect of minute Cr additions on dendritic growth directions in Al-20 wt pct Zn alloy has been investigated. As first evidenced by Gonzales and Rappaz (Metall Mater Trans A 37:2797-2806, 2006) Al-Zn alloys exhibit a Dendrite Orientation Transition (DOT ...

SPRINGER2020

Early Stages of Precipitation In Aluminum Alloys by First-Principles and Machine-Learning Atomistic Simulations

Daniele Giofré

Age hardening induced by the formation of (semi)-coherent precipitate phases is crucial for the processing and final properties of the widely used Al-6000 alloys despite the early stages of precipitation are still far from being fully understood. This cruc ...

EPFL2018

Dislocation Cross-Slip in Face-Centered Cubic Solid Solution Alloys

Wolfram Georg Nöhring

The mechanical strength of metals depends on their resistance against various microscopic deformation processes. In ductile metals, the most important process is shearing of the crystal lattice by dislocations. One of the fundamental aspects of dislocation ...

EPFL2018

Neural network potential for Al-Mg-Si alloys

Till Junge, William Curtin, Michele Ceriotti, Daniele Giofré

The 6000 series Al alloys, which include a few percent of Mg and Si, are important in automotive and aviation industries because of their low weight, as compared to steels, and the fact their strength can be greatly improved through engineered precipitatio ...

Amer Physical Soc2017

Atomistic mechanisms of hydrogen embrittlement

Ali Tehranchi

The detrimental effects of the H on the mechanical properties of the metals are known for more than a century. One of the most important degradation mechanisms is H embrittlement (HE). In this thesis, we examined a few famous proposed mechanisms in the fie ...

EPFL2017

Strength and fracture of silicon second-phase particles in aluminium casting alloys

Martin Guillermo Mueller

The mechanical behaviour of metallic materials that have a microstructure composed of a brittle phase embedded in a ductile matrix is dictated by a complex interplay of factors such as local phase properties, cohesive properties, geometrical characteristic ...

EPFL2017

Solute strengthening in random alloys

William Curtin, Céline Varvenne, Maryam Ghazisaeidi

Random solid solution alloys are a broad class of materials that are used across the entire spectrum of engineering metals, whether as stand-alone materials (e.g. Al-57xxx alloys) or as the matrix in precipitate strengthening materials (e.g. Ni-based super ...

Elsevier2017

Influence of icosahedral short range order on diffusion in liquids: A study on Al-Zn-Cr alloys

Michel Rappaz, Güven Kurtuldu

It has been shown recently that minute additions of Cr in Al-Zn alloys refine the solidified grain structure and induce multiply-twinned grains which can only be explained if the icosahedral symmetry is considered (Kurtuldu et al., 2013). It has been sugge ...

Elsevier2016

Secondary hardening in Co-Ni-Cr super-alloy investigated by Mechanical Spectroscopy

Daniele Mari, Raffaele Cosimati

The effects of thermal treatments on a Co-Ni-Cr super-alloy in the temperature range from 250 degrees C to 900 degrees C, resulting in secondary hardening, have been studied by Mechanical Spectroscopy. The simultaneous evolution of the internal friction sp ...

Elsevier2016