Publications by Andreas Mortensen

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It was recently shown that silicon particles in heat-treated Al–Si casting alloys can contain flaws such as surface pinholes and grooves, which cause varying degrees of reduction in the in situ particle fracture strength and hence influence the mechanical ...

Le plomb ajouté dans le cuivre et ses alliages est présent aux joints de grains à l'équilibre capillaire sous la forme de lentilles dont la géométrie est gouvernée par leur angle dièdre. Une méthode de mesure de l'angle dièdre permettant d'accéder à une valeur précise pour chaque inclusion a été développée et appliquée aux inclusions individuelles dans un alliage Cu-1Pb. Les résultats obtenus sur une série d'inclusions montrent une grande dispersion à l'échelle d'un échantillon. Cette observation est interp

It is shown that extrusion of "FORMGRIP" precursor material prior to baking leads to accelerated foaming and finer, more uniform cell structures. This effect is correlated with microstructural observations made on the precursor materials and on the foams, It is thought that, while extrusion apparently does not extensively fracture the gas-generating hydride particles, it does induce sonic damage to their protective surface oxide layers. Removal of the porosity normally present in as-cast precursors may also

A method is presented for studying fibre damage in continuous fibre reinforced composites. It is based on contrasting the transmission of light through intact translucent fibres with the light through fractured or dead-ended fibres. The method is applied in order to detect processing-induced fibre fractures in aluminium reinforced with continuous alumina fibres.

The influence of the quench rate after solution treatment on the bendability of AA6016 aluminum alloy sheets was investigated. Crack initiation during bending tests is found to be independent of quench rate whereas crack propagation is decreased after rapi ...

Capillary phenomena pertinent to solidification processing of metal matrix composite materials are reviewed. Recent research on the design of wettability measurement methods that are pertinent to metal matrix composite fabrication and overcome limitations of the sessile drop technique is presented. The discussion also addresses non-chemical aspects of wetting of a reinforcement by liquid metal, with emphasis on the infiltration process, and reviews engineering approaches for improved wettability and control

The method comprises at least the following steps: - exposing a substrate to focused laser irradiation at a preselected series of locations that trace a subset of the substrate volume that is connected to the surface of the substrate; some subsets of subst ...

We consider a material having a constant true activation volume and estimate the apparent activation volume that it displays in cyclic creep or ratcheting. We show that cyclic stresses have an effect on the measured value, and that this can be accounted fo ...

The electrical conductivity of metallic foams varies strongly with porosity. Data are presented for replicated open-pore microcellular metal over a wide range of relative density. These data, together with data from the literature for different foam struct ...

The initial compaction under uniaxial hot-pressing conditions of titanium monotapes containing silicon carbide fibres is studied for variable matrix/fibre volume ratio, temperature (800-950 degrees C) and compaction stress (10-40 MPa). The matrix compaction rate is predominantly affected by the latter two variables, less by temperature. The sample pore structure is strongly influenced by the preform packing characteristics including fibre-to-matrix volume ratio and irregularities in fibre arrangements.

Reactive infiltration processing was investigated in the NiAl system using nickel-powder and nickel-wire preforms. Inhomogeneous microstructures were often obtained with powder preforms which had high surface-to-volume ratio, low permeability and irregular infiltration paths. Homogeneous NiAl could be obtained with nickel-wire preforms which had lower surface-to-volume ratio, higher permeability and regular infiltration paths. NiAl composites reinforced with short molybdenum fibers and long tungsten and sap

A new casting process for fabrication of particle-reinforced metals is presented whereby a composite of particulate reinforcing phase in metal is first produced by pressure infiltration. This composite is then diluted in additional molten metal to obtain the desired reinforcement volume fraction and metal composition. This process produces a pore-free as-cast particulate metal-matrix composite. This process is demonstrated for fabrication of magnesium-matrix composites containing SiC reinforcements of avera

Diametric compression testing can be used to measure the hoop strength of spherical particles if one uses platens whose deformation behaviour is tailored in a way that allows the particles to sink sufficiently far into the platens before particle fracture ...

Approximate but simple expressions for the rate of isothermal coarsening of secondary dendrite arms are presented. Their derivation differs from previous work in that (a) focus is placed on growing dendrite arms, which simplifies the derivation, and (b) the effect of a finite volume fraction solid is taken into account. Expressions for isothermal coarsening are then integrated to predict the final dendrite arm spacing in a cast dendritic microstructure. Coarsening rates predicted for Al-Cu alloys, succinoni

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 ...

Composite material combining: - a precious metal or an alloy containing a precious metal, - and a boron-based ceramic having a melting point above that of said precious metal and a density at most equal to 4 g/cm3. ...

Dataset corresponding to the following manuscript: Slagter, A., Setyadji, J.A., Vogt, E.L. et al. Nanoindentation Hardness and Modulus of Al2O3–SiO2–CaO and MnO–SiO2–FeO Inclusions in Iron. Metall Mater Trans A (2024). https://doi.org/10.1007/s11661-024-0 ...

Andreas Mortensen

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Silicon particle pinhole defects in aluminium–silicon alloys

Corrélation entre la forme d'inclusions intergranulaires et l'énergie de joints de grains dans un alliage Cu-1Pb

The effect of prior deformation on the foaming behavior of 'FORMGRIP' precursor material

Transmitted light microscopy of a fibre reinforced metal

Influence of quench rate and microstructure on bendability of AA6016 aluminum alloys

Interfacial phenomena in the solidification processing of metal matrix composites

Small-scale metal castings, small-scale metal/transparent composite structures and process to produce same

On measured activation volumes as relevant to ratcheting or cyclic creep

The electrical conductivity of microcellular metals

On the steady-state creep of microcellular metals

Initial-Stage Hot-Pressing Of Sic Fibre/Ti Monotapes

Reactive infiltration processing of bulk and fiber-reinforced NiAl

Fabrication Of Cast Particle-Reinforced Metals Via Pressure Infiltration

On the diametric compression strength test of brittle spherical particles

Graded open-cell aluminium foam core sandwich beams

On the rate of dendrite arm coarsening

Functional grading of metal foam cores for yield-limited lightweight sandwich beams

Preform to produce metallic foam

Composite material comprising a precious metal, manufacturing process and use of such a material

Nanoindentation hardness and modulus of Al2O3-SiO2-CaO and MnO-SiO2-FeO inclusions in iron