Publications de Jonas Valloton

Numerical Model of Rapidly Solidified Droplets of Al-33 Wt Pct Cu Eutectic Growth

Rapid solidification of Al-Cu droplets of eutectic composition was carried out using Impulse Atomization (a type of drop tube). Two distinct morphologies were observed: an irregular undulated eutectic assumed to form during recalescence, followed by a regu ...

SPRINGER2022

Rapid solidification of Al-Cu droplets of near eutectic composition

Michel Rappaz, Jonas Valloton

Near eutectic Al-Cu droplets were rapidly solidified by Impulse Atomization. A wide range of microstructural scales was obtained at different cooling rates and undercoolings. The micrographs of the investigated samples revealed two distinct zones of differ ...

IOP PUBLISHING LTD2019

Modeling of peritectic coupled growth in Cu-Sn alloys

Michel Rappaz, Jonas Valloton, Jonathan Dantzig

In directional solidification experiments on hypoperitectic Cu-Sn alloys at low velocity and high thermal gradient, both lamellar and fibrous coupled peritectic growth patterns have been observed. Two phenomena that had not been observed in previous experi ...

Elsevier2013

Phase Competition in Peritectic Cu-Sn Alloys during Solidification at Low Speed in a Diffusive Regime

Jonas Valloton

EPFL2012

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

Michel Rappaz, Jean-Daniel Wagnière, Jonas Valloton

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

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, André Phillion, Marco Stampanoni

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

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