Publications de Andreas Mortensen

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The injection of pure liquid metal into a fibrous preform initially at a temperature below the melting point of the metal results in partial solidification of the metal as it contacts the fibers. If the infiltrating metal is superheated, continued infiltration remelts this solid metal at a sharp front which propagates through the fiber preform. Because the permeability of the remelted region is greater than that of the partially solidified region, there is a driving force for the remelted region to advance

The Portevin- Le Chatelier effect in an AlCu/Al2O3 composite with a large volume fraction (60%) of ceramic particles is investigated from a numerical point of view using a strainageing visco-plastic material model for the metallic matrix and several differ ...

Fibres fracture gradually during the fatigue cycling of continuous alumina fibre reinforced aluminium. The number of fibre breaks increases linearly with the logarithmic cycle number, depends on the maximum stress and the stress ratio, and agrees with publ ...

This contribution draws practical implications of a recently published estimation of the tensile ductility in laminated composites made of two ductile materials, typically metals or alloys, which harden as both the strain and the strain-rate increase. To t ...

Al-Cu matrix composites with a high volume fraction of alumina particles (41-62%) prepared by gas-pressure infiltration are characterized in tension and chevron-notch fracture testing before and after heat-treatment. Their mechanical behaviour is shown to depend markedly on the matrix structure and flow stress, and also on the nature and size of the reinforcement particles. Al-Cu matrix composites free of coarse Al2Cu matrix intermetallics and reinforced with 60 vol% high-strength polygonal alumina particle

Wetting and sticking of soda-lime glass on two types of stainless steel as well as on platinum and vitreous carbon substrates are studied in a neutral gas atmosphere between 860 and 1200degreesC. Wetting is measured by the "transferred drop" version of the sessile drop technique, enabling fully isothermal spreading kinetics to be monitored. Sticking is investigated by measuring the temperature of glass drop detachment from the substrate during cooling below the vitreous transition temperature. Characterizat

Curing kinetics of commercial polycarbosilane have been measured using differential scanning calorimetry in air between 140 and 220 degrees C. It was found that the total heat of curing increases linearly with temperature. At constant temperature, the rate of heat release can be described by the sum of a first-order kinetic term, and a transient term of much higher order, both depending on the fraction of remaining reaction enthalpy. Constants for both terms increase according to the Arrhenius law, with rou

Fundamentals of materials processes wherein a reinforcing phase is combined with bulk molten metal are reviewed. Capillary phenomena which govern the incorporation of the reinforcement into the matrix are discussed first, with focus on thermodynamics, mechanics, and chemistry of wetting. Engineering strategies that have been adopted to increase reinforcement wettability are also addressed. Relevant transport phenomena are covered next, with focus on the infiltration process and the rheology of composite slu

The effect of titanium additions on the interface and mechanical properties of infiltrated Cu8 wt%Al-Al2O3 composites containing 57 +/- 2 vol% ceramic are investigated, exploring two different Al2O3 particle types and four different Ti concentrations (0, 0 ...

Elastoplastic toughness testing of pure aluminium replicated foam is conducted following a J-procedure adapted from the ASTM E1820-08a standard using disc-shaped compact tension specimens. Tests cover a wide range of foam relative density V-m (10-24%). Res ...

We implement the C-shaped sample test method and micro-cantilever beam testing to measure the local strength of microscopic, low-aspect-ratio ceramic particles, namely high purity vapor grown a-alumina Sumicorundum (R) particles 15-30 mu m in diameter, kno ...

Models derived in petroleum engineering and soil science for flow of two immiscible fluids in a porous medium are extended to the infiltration of ceramic preforms by a liquid metal. SAFFIL alumina fiber preforms are infiltrated with an aluminum matrix in a series of interrupted unidirectional and isothermal experiments at various low applied pressures, to measure profiles of the volume fraction of metal along the length of the reforms. Comparison of experimental data with theory reveals the existence of a p

When wetting is promoted by interfaces, the rate at which the liquid spreads over the solid substrate is controlled by the rate at which the well-wetted interfacial product can be formed along the liquid/solid/atmospheric triple line. If this reaction involves a reactive alloy addition to the liquid, the rate of spreading can be limited by two phenomena. A simplified analysis of diffusion- limited reactive spreading of Cu-Sn-Ti alloys on vitreous carbon was conducted based on the assumption that the interfa

We document that in unstressed, undeformed, samples of pure iron containing silica inclusions precipitated by melt deoxidation, the iron matrix and a small fraction of the silica inclusions are locally separated at room temperature by a void. Thermal cycli ...

The dihedral angle shown by intergranular lead inclusions in Cu-1 wt.% Pb alloys is measured varying the purity of the metal and the temperature. Several measurement methods are used and compared, namely classical two-dimensional (2D) methods based on meta ...

Al-6.4 wt% Ni open-cell foams produced by replication are tested in compression and in tension at room temperature and creep tested in tension at 450C. The mechanical behaviour of this foam at room temperature is consistent with that observed for other ope ...

We extend the analysis of Hutchinson and Neale (Hutchinson JW, Neale KW. Acta Metall 1977;25:839) and Ghosh (Ghosh AK. Acta Metall 1977;25:1413) predicting the tensile elongation to failure of strain-rate-dependent plastic materials to two-phase composites deforming quasistatically according to the equistrain rule of mixtures. The analysis incorporates the influence of work hardening and strain-rate hardening in both composite constituent phases. It is shown that the problem can be formulated in a manner th

Two major classes of models for the multiaxial yield behaviour of aluminium foams are found in the literature. One is based on the foam properties and uses empirical constants determined by fitting of experimental data. The other is based on a mean-field approach where the foam is considered as a two-phase composite of Al matrix containing void inclusions. The present investigation is a confrontation of these models with the measured behaviour of replicated microcellular aluminium using multi-axial testing.

Copper and its alloys generally display a severe reduction in ductility between roughly 300 and 600 degrees C, a phenomenon variously called 'intermediate temperature embrittlement' or 'ductility trough behaviour'. This review of the phenomenon begins by p ...

Raman spectroscopy demonstrates that silica inclusions in arc-melted samples of Hernández-Escobar et al. (Metall Mater Trans B 55B:1–7, 2024) were amorphous. This excludes allotropic phase transformations within silica as a possible mechanism driving interfacial debonding within those samples. Coupling this result with Pindar and Pande (Metall Mater Trans B 56B:1–9, 2025) leads to conclude that allotropic transformations of either the matrix or inclusion can drive the interfacial debonding of silica inclusi

Andreas Mortensen

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Infiltration of fibrous preforms by a pure metal: Part IV. Morphological stability of the remelting front

Finite element simulation of the Portevin-Le Chatelier effect in highly reinforced metal matrix composites

Damage accumulation during cyclic loading of a continuous alumina fibre reinforced aluminium composite

Designing laminated metal composites for tensile ductility

Fracture of aluminium reinforced with densely packed ceramic particles: influence of matrix hardening

Wetting, interfacial interactions and sticking in glass/steel systems

Processing Of Microcellular Sic Foams .1. Curing Kinetics Of Polycarbosilane In Air

Solidification Processing Of Metal Matrix Composites

Infiltrated Cu8Al-Ti alumina composites

Fracture toughness of Al replicated foam

The local strength of individual alumina particles

Capillarity in isothermal infiltration of alumina fiber preforms with aluminum

Diffusion-limited reactive wetting: Spreading of Cu-Sn-Ti alloys on vitreous carbon

Phase Transformation-Induced Interfacial Debonding of Silica Inclusions in Iron

Dihedral Angles in Cu-1wt.%Pb: Grain Boundary Energy and Grain Boundary Triple Line Effects

Microstructure, Strength and Creep of Aluminium-nickel Open Cell Foam

An analysis of the tensile elongation to failure of laminated metal composites in the presence of strain-rate hardening

Multiaxial Yield Behaviour of Al Replicated Foam

Intermediate temperature embrittlement of copper alloys

Interfacial Debonding of Amorphous Silica Inclusions in Iron Dominated by the Austenite-to-Ferrite Transformation