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Michel Rappaz

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Related publications (85)

Page 2 of 5

Phase-field modeling of the dendrite orientation transition in Al-Zn alloys

Michel Rappaz, Paolo Di Napoli, Jonathan Friedli

With a few exceptions, phase-field simulations of dendritic growth in cubic materials have been modeled using simple expressions for the interfacial energy anisotropy and with strong anisotropy. However, recent experimental results show that the Dendrite O ...

Iop Publishing Ltd2012

Effective hydrogen diffusion coefficient for solidifying aluminium alloys

Michel Rappaz, Ludger Weber

An effective hydrogen diffusion coefficient has been calculated for two solidifying Al - 4.5 wt.% Cu and Al - 10 wt.% Cu alloys as a function of the volume fraction of solid. For this purpose, in situ X-ray tomography was performed on these alloys. For eac ...

Elsevier2011

Influence of Minor Additions on Icosahedral Short-Range Order (ISRO) and Its Consequences on Nucleation and Solidification Growth Kinetics in fcc Alloys

Michel Rappaz

The present contribution reviews the recent progress related to the influence of icosahedral short-range order (ISRO) and icosahedral quasicrystal (iQC) formation on the solidification of fcc alloys through minor solute element additions. From intensive cr ...

SPRINGER INDIA2018

Connectivity of Phases and Growth Mechanisms in Peritectic Alloys Solidified at Low Speed: an X-Ray Tomography Study of Cu-Sn

Michel Rappaz, Jonas Valloton

The variety of microstructures that form at low solidification speed in peritectic alloys, bands, and islands, or even coupled (or cooperative) growth of the primary alpha and peritectic beta phases, have been previously explained by nucleation-growth mech ...

Springer Verlag2010

Effects of Ni additions, trace elements and solidification kinetics on microstructure formation in Sn-0.7Cu solder

Michel Rappaz

Five ternary Sn-0.7Cu-xNi alloys with nickel contents in the range 0-1000 ppm have been directionally solidified at different growth rates. The competition between primary tetragonal Sn cells/dendrites, eutectic and primary Cu6Sn5 is interpreted with phase ...

Elsevier2011

Growth of intermetallic compounds in the Au-In system: Experimental study and 1-D modelling

Michel Rappaz, Aïcha Hessler-Wyser, Léa Deillon

The gold indium system is of primary interest for bonding processes such as solid liquid interdiffusion bonding. In order to optimize the manufacturing parameters, it is essential to know which intermetallic compounds (IMCs) are formed when solid Au and li ...

Elsevier2014

Growth directions in directionally solidified Al-Zn and Zn-Al alloys near eutectic composition

Michel Rappaz, Martin Rhême, Frédéric Claude Denis Dreyer

Growth directions and crystallographic orientations of solidification microstructures have been measured in Al-Zn alloy near the eutectic composition. Al dendrites in Al-92 wt.% Zn alloy were found to grow along the I 10) directions while Zn dendrites in A ...

Elsevier2008

Grain selection and texture evolution in directionally solidified Al-Zn alloys

Michel Rappaz, Frédéric Claude Denis Dreyer

In a recent contribution, we have reported that dendrites in the aluminum-zinc binary system can change their growth direction continuously from {100} to {110} as the concentration of zinc CZn increases from 5 to 90 wt pct.[1] This was interpreted as an in ...

Springer US2008

Development of a laser-based heating system for in situ synchrotron-based X-ray tomographic microscopy

Michel Rappaz

Understanding the formation of materials at elevated temperatures is critical for determining their final properties. Synchrotron-based X-ray tomographic microscopy is an ideal technique for studying such processes because high spatial and temporal resolut ...

International Union of Crystallography2012

Peritectic reaction on the Al-rich side of Al-Cr system

Michel Rappaz, Güven Kurtuldu

A long lasting controversy on the nature of the reaction between liquid, Al and Al45Cr7 has been ended by planar front solidification experiments of Al-Cr alloy in a Bridgman furnace. Cr depletion in the liquid ahead of the quenched planar interface proves ...

Elsevier2015

Progress in modelling solidification microstructures in metals and alloys. Part II: dendrites from 2001 to 2018

Michel Rappaz, Wilfried Kurz

This is the first account of the history of modelling dendritic and cellular solidification. While Part I reviewed the progress up to the year 2000 [Kurz W, Fisher DJ, Trivedi R. Progress in modelling solidification microstructures in metals and alloys: de ...

TAYLOR & FRANCIS LTD2021

The influence of 0-0.1 wt.% Ni on the microstructure and fluidity length of Sn-0.7Cu-xNi

Michel Rappaz

Alloys based on the Sn-0.7Cu-xNi system are potential Pb-free solders. In this paper we report on the solidification characteristics and microstructures of Sn-0.7Cu alloys containing 0-1,000 ppm nickel. The microstructural observations show that increasing ...

Springer Verlag2008

3D Phase-Field Simulation of Micropore Formation during Solidification: Morphological Analysis

Michel Rappaz, Alain Jacot, Hossein Meidani

A 3D multiphase-field (PhF) model has been developed in order to study the formation of a micropore constrained to grow in a solid network (i.e., pinching effect). The model accounts for the pressure difference due to capillarity between liquid and gas, th ...

Iop Publishing Ltd2012

A 3-D coupled hydromechanical granular model for simulating the constitutive behavior of metallic alloys during solidification

Michel Rappaz, Jean-Marie Drezet, Meisam Sistaninia

A three-dimensional (3-D) coupled hydromechanical granular model has been developed and validated to directly predict, for the first time, hot tear formation and stress strain behavior in metallic alloys during solidification. This granular model consists ...

Elsevier2012

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

A Granular Model of Equiaxed Mushy Zones: Formation of a Coherent Solid and Localization of Feeding

Michel Rappaz, Stéphane Vernède

The gradual transformation of a mushy zone during alloy solidification, from a continuous liquid film network to a fully coherent solid, has been simulated using a granular model. Based on a Voronoi tessellation of a random set of nucleation centers, solid ...

2006

Study of the twinned dendrite tip shape II: Experimental assessment

Michel Rappaz, Marco Cantoni, Pierre Burdet

The favorable growth kinetics of twinned dendrites can be explained by their complex morphology, multiple side branching mechanisms, growth undercooling and tip morphology. Three models were proposed for the twinned dendrite tip shape: (i) a grooved tip sa ...

2011

Influence of Cr on the nucleation of primary Al and formation of twinned dendrites in Al-Zn-Cr alloys: Can icosahedral solid clusters play a role?

Michel Rappaz, Güven Kurtuldu

The equiaxed solidification of Al-20 wt.% Zn alloys revealed an unexpectedly large number of fine grains which are in a twin, or near-twin, relationship with their nearest neighbors when minute amounts of Cr (1000 ppm) are added to the melt. Several occurr ...

Elsevier2013

Competition of the primary and peritectic phases in hypoperitectic Cu-Sn alloys solidified at low speed in a diffusive regime

Michel Rappaz, Jonas Valloton, Jean-Daniel Wagnière

Directional solidification experiments on hypoperitectic Cu-Sn alloys have been performed at very low velocity in a high thermal gradient to ensure planar front growth of both phases. The diameter of the sample has been reduced to 500 mu m to strongly redu ...

Elsevier2012

Solidification microstructures and solid-state parallels: Recent developments, future directions

Michel Rappaz, Wilfried Kurz

Rapid advances in atomistic and phase-field modeling techniques as well as new experiments have led to major progress in solidification science during the first years of this century. Here we review the most important findings in this technologically impor ...

Elsevier2009