Publications by Andreas Mortensen

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A process for producing a metal article containing at least 10% interconnected porosity, using a preform (11), comprising: mixing an organic binder, a wetting agent and a granular material, to obtain a mouldable paste that combines 10 vol. pct. or more of ...

We prepare multi-component transition monocarbides of chosen composition by arc-melting together a pre-alloy of the transition metals and cast iron. Based on the elements Ti, Ta, V, Nb and W, 51 different binary, ternary and quaternary compositions are pro ...

We address the effect of elastic inhomogeneity on elastic modulus and hardness determinations made by depth-sensing indentations performed on individual particles embedded within a matrix of different elastic modulus. Finite element simulations and nanoind ...

Common metal additive manufacturing technologies require intensive energy sources such as lasers to achieve the melting and bonding of a metallic feedstock. This leads to a sizeable carbon footprint especially for reflective materials such as aluminium. Moreover, it induces complex and turbulent melt pool dynamics leading to stochastic defect formation mechanisms that are hence difficult to suppress. We aim to propose an alternative approach similar to what is now practised on a large scale with thermoplast

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 ...

The infiltration of a non-wetting liquid, such as molten metal, into a porous solid, such as a ceramic preform, is influenced by the wetting angle of the liquid on the solid. The link between local wetting and the minimum pressure required for initiation o ...

The tensile failure of unidirectional alumina fibre reinforced aluminium is studied in uniaxial loading along the fibre axis. The tensile strength is measured as a function of matrix yield strength, which is varied by varying the testing temperature, from ...

The strength of the interface between iron (Fe) and individual spherical silica (SiO2) inclusions of 5 +/- 1 mu m diameter is measured by means of in-situ micro-cantilever bending tests conducted under displacement control within a scanning electron micros ...

Plastic deformation under uniaxial longitudinal tension and compression is investigated for pure aluminum reinforced with a high volume fraction of parallel alumina fibers. The matrix sub-structure is also examined in transmission electron microscopy. The aim is to study the in situ room-temperature mechanical behavior, particularly the work-hardening rate, of pure aluminum when reinforced with a high volume fraction of chemically inert ceramic reinforcement. The matrix substructure prior to deformation, co

We investigate processing-microstructure relationships in the production of Al2O3 particle reinforced copper composites by solidification processing. We show that during production of the composites by gas-pressure infiltration of packed Al2O3 particle pre ...

Metal matrix composites composed of high-purity aluminum and Du Pont PRD-166 continuous zirconia-stabilized polycrystalline alumina fibers are fabricated by liquid metal infiltration using three different casting procedures. The microstructure of the composites is analyzed using optical and electron microscopy, including analytical electron microscopy. It is found that discrete faceted particles of ZrAl3 form at the interface and grow into the matrix of samples processed above the melting point of the matri

The influence of particle size and particle type on the fracture toughness of aluminium matrix composites is investigated using model composites of 99.99% purity aluminium reinforced with particles of alumina and boron carbide. These composites are produced by gas pressure infiltration, and feature a volume fraction of reinforcement near 50 vol pet. The average particle size is varied between 5 and 35 mum. Fracture properties are determined using the single specimen J-integral test method. Observations of c

In this work, brazed joints between samples of 316L stainless steel (316LSS) are formed using the Ag155 brazing filler metal. As an additional aspect of the investigation, the joints combine stainless steel formed by conventional processing and by additive ...

Multiaxial experiments are performed on replicated aluminium foam using a custom-built apparatus. The foam structure is isotropic, and features open monomodal pores 75 mu m in average diameter. Plane stress (sigma(1), sigma(2), sigma(3) = 0) and axisymmetr ...

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 ...

A process is presented for the production of periodic cellular structures based on investment casting of Al-12 wt%Si alloy within a mould that is made of table salt (NaCl) packed around a sacrificial PLA polymer template. Moulding begins by pouring salt gr ...

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 ...

In a previous article,[1] a theoretical analysis was developed to describe the infiltration of fiber preforms by a binary alloy, and its solution was given for unidirectional adiabatic infiltration under constant applied pressure. This article further develops the analysis by proposing a model to predict the permeability of fibrous preforms containing solidified primary metal, by deducing the final composite microstructure from processing parameters, and by addressing the influence of external cooling on ma

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 ...

We present an analytical micromechanical model designed to simulate the tensile stress-strain behaviour and failure of damaging composites containing a high volume fraction of reinforcing particles. One internal damage micromechanism is considered, namely ...

Andreas Mortensen

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Porous metal article and method of producing a porous metal article

Processing and micro-mechanical characterization of multi-component transition MC carbides in iron

Nanoindentation of embedded particles

Magnetic Field-Assisted Direct Liquid Metal Deposition

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

Simulating Infiltration as a Sequence of Pinning and De-pinning Processes

Tensile strength of axially loaded unidirectional Nextel 610 (TM) reinforced aluminium: A case study in local load sharing between randomly distributed fibres

Room-temperature strength of the interfacial bond between silica inclusions and iron

Structure And Room-Temperature Deformation Of Alumina Fiber-Reinforced Aluminum

Al2O3 particle rounding in molten copper and Cu8wt%Al

Chemical stability of zirconia-stabilized alumina fibers during pressure infiltration by aluminum

Fracture toughness determination of high volume fraction particle reinforced aluminium matrix composites

Influence of Testing Temperature on the Mechanical Performance of Brazed Conventionally and Additively Manufactured 316L Stainless Steel Joints

Multiaxial yield behaviour of Al replicated foam

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

Investment casting of periodic aluminum cellular structures using slurry-cast table salt moulds

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

Infiltration of fiber preforms by a binary alloy: Part II. Further theory and experiments

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

Ductile-to-brittle transition in tensile failure of particle reinforced metals