Yves Gaillard

Yves Gaillard
Institut FEMTO-ST | FEMTO ST · Department of Applied Mechanics

PhD

About

44
Publications
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907
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Additional affiliations
January 2005 - April 2008
Universitat Politècnica de Catalunya
Position
  • PostDoc Position

Publications

Publications (44)
Article
This work presents an approach to simultaneously identify reliable elasto-plastic properties of a 100 nm amorphous alumina film and plastic properties of its silicon substrate by the Finite Element Model Updating (FEMU) method, using exclusively nanoindentation P−h curves. A 2D axisymmetric finite element model simulates the nanoindentation tests,...
Article
Full-text available
This work deals with the indentation analysis of nanocolumnar thin films and the difficulties encountered to deduce relevant mechanical parameters by this methodology. SiO2 thin films prepared by physical vapour oblique angle deposition with different nanocolumnar microstructures have been subjected to indentation analysis. Despite the fact that th...
Article
Full-text available
A FeCoNi(B 0.5 Si 0.5) high-entropy alloy with the face-centered cubic (FCC) crystal structure was synthesized by mechanical alloying and spark plasma sintering (SPS). Phase evolution, microstructure, morphology and annealing behaviors were investigated. It was found that a single FCC solid solution appears after 50 h of milling. The grain size was...
Article
Full-text available
This study aims to model, by using a finite element method, the relationship between the hardness and the period Λ of metal/nitride multilayer coatings (Ti0.54Al0.46/Ti0.54Al0.46N)n in order to understand the increase of the hardness at the low periods [1] and then optimise the multilayer coating architecture to obtain the best mechanical propertie...
Article
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Instrumented nanoindentation is widely used to extract the material properties from the measured force-displacement curves. In this work, the uniqueness/non-uniqueness of the intrinsic viscoelastic properties of materials determined by nanoindentation during load-unload tests is investigated. A four-parameter viscoelastic law with constant Poisson'...
Article
The information richness of imprints topographies obtained after Berkovich nanoindentation tests at grain scale is assessed for identifying all or part of the parameters of a single crystal plasticity law. In a previous paper (Renner et al., 2016), the strong potential of imprints topographies has been shown through a large experimental campaign co...
Article
Full-text available
The use of grid nano-indentation as a full-field measurement tool to investigate the properties of heterogeneous materials is described. Contrarily to the reported approaches which rely on statistical analysis, the mechanical properties fields are analyzed herein relying on a topological description of the sample. The spatial convolution function i...
Article
A bio-based reactive phosphate flame retardant derived from iso-eugenol was synthesized and fully characterized (1H,13C,31P NMR, FTIR, MS) with the aim of improving flame retardancy behavior of bio-based epoxy thermosets. This new green flame retardant, diepoxy-iso-eugenol phenylphosphate (DEpiEPP) was then copolymerized either with conventional di...
Conference Paper
Full-text available
MANITOO est une implémentation orientée objet en C++ permettant la résolution de pro-blèmes non-linéaires par Méthode Asymptotique Numérique. Principalement dédiée à la simulation par éléments finis en mécanique des milieux continus, on présente ici les principales caractéristiques.
Preprint
Full-text available
MFront is a tool which allows easy implementation of arbritrary complex mechanical behaviours in an efficient way. Those implementations are portable between various finite element solvers and solvers based on FFT. MFront is part of the open-source TFEL project. The purpose of this paper is to highlight a selected set of features introduced in Vers...
Article
The micro-mechanical (Young's modulus and hardness) and tribological properties, as well as the scratch resistance of Co-Mo/TiO2 nano-composite coatings were investigated. The coating was found to be harder and stiffer than the substrate (pure cobalt). Low residual stresses were also derived from Stoney's equation (type I stress). The corrosion beh...
Article
Biobased diepoxy synthons derived from isoeugenol, eugenol or resorcinol (DGE-isoEu, DGE-Eu and DGER, respectively) have been used as epoxy monomers in replacement of the diglycidyl ether of bisphenol A (DGEBA). Their curing with six different biobased anhydride hardeners leads to fully biobased epoxy thermosets. These materials exhibit interesting...
Article
This paper investigates the mechanical properties of hyper deformed wires of Ti-26 at.%Nb (Ti-26Nb) alloy that can be equally expressed as Ti-40.5 wt%Nb. These wires obtained by hot drawing process have a diameter of 85 μm and 285 μm, respectively. The effect of a short heat treatment at 748 K for 600 s was also investigated. The influence of the h...
Article
A novel lignin-based synthon, diglycidylether of iso-eugenol (DGE-isoEu) is used as a prepolymer for the preparation of thermosetting resins. DGE-isoEu is synthesized in a two-step procedure with a satisfactory yield from bio-based iso-Eugenol (isoEu, 2-Methoxy-4-(1-propenyl)phenol) catalytically fragmented from lignin in an organosolv process. DGE...
Article
Fundamental deformation mechanisms of FCC materials under indentation have been probed at the grain scale. Experimental tests have been conducted on large-grained annealed and cold-worked polycrystalline nickel samples with a Berkovich indenter. Indentation axes have been chosen to be close to the three main crystallographic directions [001], [101]...
Article
Full-text available
With the aim of providing better control of shooting experiments performed with replicas of prehistoric projectiles, we have conducted an instrumental archaeology study on the efficiency of prehistoric projectile points by placing emphasis on their adhesion and ballistic characteristics. In order to avoid any reproducibility problems, hafting adhes...
Article
Blends of rosin and beeswax were studied in terms of their thermal and mechanical behaviors. Their glass transition and α relaxation were both characterized, either by differential scanning calorimetry or by dynamic mechanical thermal analysis. In this study, we focused particularly on the impact of the microstructure on the mechanical properties,...
Article
Full-text available
A series of nanoindentation tests has been carried out with TiO2 films produced by physical vapour deposition (PVD) under different conditions. Films with different microstructures and crystallographic structures have been prepared by changing experimental parameters such as the temperature of the substrate, the deposition angle (by the so-called g...
Chapter
Yttria-doped zirconia ceramics have proven to possess excellent mechanical properties, particularly strength and fracture toughness, which arise from the submicron average grain size and from the transformation of the tetragonal phase to monoclinic, which is accompanied by an increment of volume of about 4%, Consequently, zirconia ceramics are used...
Article
Full-text available
This paper presents a study of the deformation mechanisms of barium titanate under nanoindentation. The (0 0 1) and (1 1 0) crystallographic orientations of BaTiO3 giant grains were indented and critical mean contact pressures for dislocation nucleation were extracted from the indentation curves. The orientation of the dislocation slip lines was id...
Article
There is an increasing usage of PVD-coated hardmetals in applications where contact loads of cyclic nature between curved surfaces are common, e.g. cold forming tools and machine components. Thus, knowledge of both the mechanical response and the damage mechanisms involved during contact fatigue of these systems is required if they want to be used...
Article
Full-text available
This article presents a nanoindentation study of polycrystalline and single crystals of yttria-doped zirconia with both tetragonal and cubic phases. Analysis of the deformation mechanisms is performed by both atomic force microscopy (AFM) and micro-Raman spectroscopy. Phase transformation from tetragonal to monoclinic phase is clearly distinguished...
Article
The ageing of zirconia under hydrothermal conditions is a key issue in many applications, as the properties and thickness of the degraded layer influence the reliability of the material. This paper presents a study by nanoindentation of the hydrothermal degradation of tetragonal zirconia polycrystals doped with yttria with a tetragonal grain size o...
Article
In applications like cold forming, where ceramic - coated hardmetals are implemented, repetitive mechanical contact induces Hertzian pressures that may cause fatigue failure. In this work, the contact response and fatigue behavior of a TiN coating deposited by PVD onto two different hardmetal grades are investigated by means of spherical indentatio...
Article
Full-text available
In this paper the formation of shear bands in columnar EB-PVD thermal barriers coatings is studied. In particular, critical parameters of nucleation of shear bands, such as contact pressure and initiation of cracks in the columns, are extracted from the experimental results. The pertinence of these parameters is discussed respecting to the stress f...
Article
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This paper gives a short review of the instrumented indentation technique when applied to ceramic layered materials. The main causes of error are commented, together with the effect of the substrate, the microstructure and the possible fracture events.
Article
Full-text available
The objective of this work is to evaluate the mechanical response obtained by nanoindentation and atomic force microscopy of degraded surfaces of zirconia doped with yttria. The starting material is a polycrystalline tetragonal zirconia doped with 2.5% yttria, which is subjected to different thermal treatments to produce duplex microstructures with...
Article
Full-text available
Electron beam-physical vapour deposited (EB-PVD) yttria-stabilized zirconia (YSZ) thermal barrier coatings have been investigated by nanoindentation. It is shown that the mechanical properties, and particularly the Young's modulus, of these coatings are closely related to their columnar microstructure. The transition from intracolumnar to intercolu...
Article
Full-text available
The instrumented indentation response of polycrystalline alumina and alumina-based ceramic multilayers with well-known residual stresses is investigated. Young's modulus and hardness were evaluated as a function of penetration depth with Berkovich and spherical indenters by continuous stiffness measurements. A size effect was observed due to the le...
Article
Full-text available
This study investigates the incipient plasticity during a nanoindentation test with a spherical indenter in magnesium oxide single crystals. The load–displacement curves show multiple pop-ins, interspaced by elastic deformation, and reveal the transition from an initial elastic deformation regime to a continuous elastoplastic one. Nanoindentations...
Article
Incipient plasticity in magnesium oxide single crystals has been investigated by nanoindentation with a spherical indenter. For very low loads, the surface deformation can be limited to a single slip line, making modelling of the deformation easier. The recently developed nanoetching technique has been used to investigate the corresponding dislocat...
Article
Full-text available
This letter is based on recent progress in the observation of dislocation distributions around nanoindentations by chemical etching. This so-called nanoetching technique is used to determine the dislocation mechanisms associated with the pop-in phenomenon in MgO and LiF. Successive stages of highly controlled chemomechanical polishing have revealed...
Article
In this paper, it is shown that combining AFM, chemical etching and controlled polishing, progressively removing thin layers of material, allows a three-dimensional reconstruction of the volume distribution of dislocations about and under nanoindentation imprints. To illustrate the method, results obtained in MgO, a material known for its simple pl...

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