Publications de Ludger Weber | EPFL Graph Search

Liquid metal infiltration of silicon based alloys into porous carbonaceous materials Part-III: Experimental verification of conversion products and infiltration depth by infiltration of Si-Zr alloy into mixed SiC/ graphite preforms

Ludger Weber, Alberto Ortona, Manoj Kondibhau Naikade, Caroline Hain, Annapaola Parrilli

Porous carbonaceous preforms, made from graphite and silicon carbide (SiC) powders, with varying graphite powder mass fractions and particle sizes, were infiltrated at 1500 degrees C and 1700 degrees C by Si-8 at. pct Zr alloy to produce dense Si-Zr-SiC co ...

ELSEVIER SCI LTD2023

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

Ludger Weber, Alberto Ortona, 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

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, Giovanni Bianchi, Alberto Ortona, Manoj Kondibhau Naikade, Caroline Hain

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

A quantum magnetic analogue to the critical point of water

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

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

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

Andreas Mortensen, Ludger Weber, Gionata Schneider, Marta Fornabaio

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

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

Andreas Mortensen, Ludger Weber, Karel Lietaert

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

Role of the electron-phonon coupling on the thermal boundary conductance of metal/diamond interfaces with nanometric interlayers

Ludger Weber, Gionata Schneider, Maïté Blank

Thermal boundary conductance (TBC) of the Ag/diamond and Au/diamond interfaces with a nanometer-thick interface layer of either nickel or molybdenum is measured by time domain thermoreflectance and modeled based on a 3-layer two-temperature model (3l-TTM). ...

2019

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

Ludger Weber, Alberto Ortona, 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

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

Influence of interfacial structural disorder and/or chemical interdiffusion on thermal boundary conductance for Ti/Si and Au/Si couples

Ludger Weber, Maïté Blank

This work aims at experimentally assessing the effect of structural disorder and/or chemical interdiffusion on thermal boundary conductance (TBC) at metal/dielectric interfaces. To this end, the TBC of Au/Si and Ti/Si interfaces was measured by time domain ...

2019

Erratum: Influence of the thickness of a nanometric copper interlayer on Au/dielectric thermal boundary conductance (vol 124, 105304, 2018)

Ludger Weber, Maïté Blank

AMER INST PHYSICS2019

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

Andreas Mortensen, Ludger Weber, Karel Lietaert

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

Influence of the thickness of a nanometric copper interlayer on Au/dielectric thermal boundary conductance

Ludger Weber, Maïté Blank

The influence of the thickness of a thin (1.5-30 nm) copper layer on the thermal boundary conductance (TBC) at the interface between gold and silicon, sapphire and diamond, respectively, was studied using Time Domain Thermoreflectance. Overall, a monotonic ...

2018

Development of a new family of phosphorous-free Pt-based bulk metallic glasses

Ludger Weber, Cyrill Werner Cattin, Maïté Blank, Hamed Kazemi

New BMGs exhibiting strong glass forming ability combined with high hardness have been developed based on the Pt-Si-B ternary system. The effects of partial substitution of platinum by transition metals of the group iron, cobalt, nickel, and copper, as wel ...

Elsevier2017

Effects of partial crystallization in Pt-Si-B-based bulk metallic glasses on glass transition and crystallization of the remaining amorphous matrix

Ludger Weber, Cyrill Werner Cattin, Hamed Kazemi, Gilles Hodel

The influence of partial crystallization on the evolution of the characteristic temperatures, i.e. of the glass transition and the onset of crystallization, the density, and the mechanical properties of the bulk metallic glass Pt(49.95)Si(6)AB(24)Ge(3)Cu(1 ...

Elsevier2017

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

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

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

Effect of Ca addition on interface formation in Al(Ca)/Al2O3 composites prepared by gas pressure assisted infiltration

Ludger Weber

The aim of the work is to study interface formation between Al2O3 particles and Al(Ca) matrix in dependence of Ca content. Aluminium matrix composites (AMC) subjected to investigation were prepared by gas pressure assisted infiltration of alumina beds with ...

Elsevier Sci Ltd2016

Effect of hydrostatic pressure on flow and deformation in highly reinforced particulate composites

Andreas Mortensen, Ludger Weber, Maria Gabriella Tarantino

Infiltrated particle reinforced composites combine a dense matrix with particles that are in mutual contact and can therefore transfer compressive stress directly from one particle to the next. As a result, these composites may combine characteristics of t ...

Elsevier2016

Influence of a Nanometric Al2O3 Interlayer on the Thermal Conductance of an Al/(Si, Diamond) Interface

Ludger Weber, Christian Monachon

The effect of an Al2O3 interlayer on the thermal conductance of metal (Al)/non-metal (diamond and silicon) interfaces is investigated using Time Domain ThermoReflectance (TDTR). Interlayers between 1.7 and 20nm are deposited on oxygen-terminated diamond an ...

Wiley-Blackwell2015

Influence of the wetting angle on capillary forces in pressure infiltration

Andreas Mortensen, Ludger Weber, Alain Léger

This work probes the influence of wetting on pressure infiltration. Pressure/saturation curves for the infiltration of packed F1000 angular alumina particle preforms by liquid Cu-Al and Sn-Al alloys are measured using an instrumented high-temperature press ...

Elsevier2015