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Ludger Weber

Cette personne a quitté l’EPFL

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Publications associées (62)

Page 1 sur 4

Mechanical properties of replicated cellular Zn and Zn1.5Mg in uniaxial compression

Andreas Mortensen, Ludger Weber

We present here a study of the mechanical behavior of cellular Zn and Zn1.5Mg with densities between 11.9 and 24.5%, produced by replication processing using NaCl as a spaceholder. Cellular Zn and Zn1.5Mg deform homogeneously during quasi-static compressio ...

ELSEVIER SCIENCE INC2019

Towards a coherent database of thermal boundary conductance at metal/dielectric interfaces

Ludger Weber, Maïté Blank

The thermal boundary conductance (TBC) of metal/dielectric couples was measured for a large variety of metals on silicon, sapphire, and diamond using time domain thermoreflectance and compared to data previously obtained on diamond. In the case of silicon, ...

2019

Capillarity in pressure infiltration: improvements in characterization of high-temperature systems

Andreas Mortensen, Ludger Weber, Raphaël Charvet, Alain Léger

In the pressure infiltration of metal matrix composites, molten metal is injected under external pressure into a porous preform of the reinforcing material. Equilibrium capillary parameters characterizing wetting for this process are summarized in plots of ...

Springer Verlag2012

Influence of processing route on electrical and thermal conductivity of Al/SiC composites with bimodal particle distribution

Ludger Weber

Al/SiC composites with volume fractions of SiC between 0.55 and 0.71 were made from identical tapped and vibrated powder preforms by squeeze casting (SC) and by two different setups for gas pressure infiltration (GPI), one that allows short (1-2 min) liqui ...

Springer US2010

In situ flow stress of pure aluminium constrained by tightly packed alumina fibres

Andreas Mortensen, Ludger Weber, Andreas Rossoll, Benedikt Moser

The in situ matrix flow stress of continuous fibre-reinforced aluminium is measured in tension along the fibre axis. We use a new, tighter, estimate for the effect differential Poisson contraction between fibres and matrix and take into consideration nonli ...

Elsevier2009

Wetting in infiltration of alumina particle preforms with molten copper

Andreas Mortensen, Ludger Weber, Maryam Bahraini Hasani

The high-temperature wettability of alumina particulate preforms by copper is investigated by means of infiltration experiments conducted at 1473 K under low oxygen partial pressure. Wetting is quantified in terms of drainage curves, which plot the volume ...

Kluwer Academic Publishers, Springer2005

Influence of diamond surface termination on thermal boundary conductance between Al and diamond

Ludger Weber, Christian Monachon

The effect of diamond surface treatment on the Thermal Boundary Conductance (TBC) between Al and diamond is investigated. The treatments consist in either of the following: exposition to a plasma of pure Ar, Ar:H and Ar:O, and HNO3:H2SO4 acid dip for vario ...

American Institute of Physics2013

Mechanical properties and cytocompatibility of dense and porous Zn produced by laser powder bed fusion for biodegradable implant applications

Andreas Mortensen, Ludger Weber

In this work, the macrotexture of dense Zn produced by laser powder bed fusion (LPBF) was studied and the mechanical properties for different tensile bar orientations were measured. The compressive strength of LPBF Zn scaffolds with five different unit cel ...

ELSEVIER SCI LTD2020

Thermal conductivity of Al-SiC composites with monomodal and bimodal particle size distribution

Andreas Mortensen, Ludger Weber

The thermal conductivity of aluminum matrix composites having a high volume fraction of SiC particles is investigated by comparing data for composites fabricated by infiltrating liquid aluminum into preforms made either from a single particle size, or by m ...

2008

A quantum magnetic analogue to the critical point of water

Henrik Moodysson Rønnow, Frédéric Mila, Ludger Weber, Bruce Normand, Ellen Fogh, Christian Rüegg, Julio Antonio Larrea Jiménez

At the liquid-gas phase transition in water, the density has a discontinuity at atmospheric pressure; however, the line of these first-order transitions defined by increasing the applied pressure terminates at the critical point(1), a concept ubiquitous in ...

2021

Studying the wettability of Si and eutectic Si-Zr alloy on carbon and silicon carbide by sessile drop experiments

Ludger Weber, Manoj Kondibhau Naikade

The contact angles of two different systems, molten silicon and a eutectic Si-8 at. pct Zr alloy and their evolution over timeon vitreous carbon and polycrystalline silicon carbide (SiC) substrates were investigated at 1500 degrees C under vacuum, as well ...

ELSEVIER SCI LTD2019

Liquid metal infiltration of silicon based alloys into porous carbonaceous materials. Part I: Modelling of channel filling and reaction phase formation

Ludger Weber, Manoj Kondibhau Naikade

A relation for an adequate pore fraction needed to obtain residual Si and C free composites via reactive Si-X alloy infiltration is presented. The volume ratio of SiC and carbonaceous phase, the composition of the infiltrating liquid and the apparent densi ...

ELSEVIER SCI LTD2022

Influence of the elastic properties of the phases on the coefficient of thermal expansion of a metal matrix composite

Martin Vetterli, Ludger Weber, Reza Tavangar Hamzehkolaei

Copper matrix composites reinforced with low thermal expansion ceramic particles, i.e. SiO2, AIN and diamond, in the range of ceramic volume fractions between 0.55 and 0.85 have been prepared by gas pressure infiltration and are characterized by their coef ...

Elsevier2011

The ESPRI project: astrometric exoplanet search with PRIMA I. Instrument description and performance of first light observations

Ludger Weber

Context. The ESPRI project relies on the astrometric capabilities offered by the PRIMA facility of the Very Large Telescope Interferometer for discovering and studying planetary systems. Our survey consists of obtaining high-precision astrometry for a larg ...

Edp Sciences S A2013

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

Liquid metal infiltration of silicon based alloys into porous carbonaceous materials. Part II: Experimental verification of modelling approaches by infiltration of Si-Zr alloy into idealized microchannels

Ludger Weber, Caroline Hain, Manoj Kondibhau Naikade

In this work, the mechanisms leading to the pore closure in reactive melt infiltration (RMI) of carbon by pure silicon and a near eutectic Si-8 at-pct Zr alloy at 1500 and 1700 degrees C under vacuum were studied. Various geometrical configurations of micr ...

ELSEVIER SCI LTD2022

Thermal conductivity and interfacial conductance of AlN particle reinforced metal matrix composites

Andreas Mortensen, Ludger Weber, Christian Monachon, Masahiro Kida

Aluminum nitride (AlN) particle reinforced metal-matrix-composites produced by pressure infiltration are characterized in terms of their thermal conductivity. The composites are designed to cover a wide range of phase contrast between the dispersed particl ...

American Institute of Physics2011

Fluid flow through replicated microcellular materials in the Darcy-Forchheimer regime

Andreas Mortensen, Ludger Weber, David Ingram, Alexandros Athanasiou-Ioannou

We extend here a “bottleneck” flow model derived earlier for incompressible fluids flowing under creeping flow conditions [Despois, J. and Mortensen, A: Acta Materialia 53 (2005) 1381] to flow regimes where inertial losses are no longer negligible, causing ...

Elsevier2017

Influence of reinforcement contiguity on the thermal expansion of alumina particle reinforced aluminium composites

Andreas Mortensen, Ludger Weber, Reza Tavangar Hamzehkolaei, Ghodratollah Roudini

Pore-free composites combining alumina particles within a matrix of pure aluminium are produced by pressure infiltration, varying systematically the degree of the contiguity, beta, of the ceramic phase by sintering prior to infiltration. The thermal expans ...

2010

Kinetic processes in the high-temperature pressure-infiltration of Al into Al2O3

Andreas Mortensen, Ludger Weber, Marta Fornabaio, Gionata Schneider

We explore the influence (i) of the interaction between aluminium and alumina, and (ii) of sodium impurities present in Bayer alumina, on the pressure infiltration of alumina particle preforms with molten aluminium. At 1000°C or above, although the alumini ...

2020