Papers by Yvonne Durandet
IOP Conference Series: Materials Science and Engineering
Lattice structures are widely used in various engineering applications due to their high weight-t... more Lattice structures are widely used in various engineering applications due to their high weight-to-strength ratio and exceptional energy absorbing performance. The feasibility of using different base materials to fabricate these cellular structures with complex geometries has been significantly broadened with the development of additive manufacturing technology. In this paper, quasi-static mechanical properties and energy absorption capability of polyamide PA 2200 (nylon 12) lattice structures were investigated by using finite element analysis (FEA) in ANSYS/LS-DYNA. Three types of lattice structures composed of body-centred cubic (BCC) unit cells were studied, including uniform lattice structures, uni-directionally graded lattice structures and bi-directionally graded structures. Finite element simulations were consistent with experimental data reported in literature. The results showed that bi-directionally graded lattice structures exhibited superior crushing resistance and highe...
Corrosion Science, Apr 1, 2011
The influence of strain rate on the properties of laser welded AM50 and AM60 magnesium alloys has... more The influence of strain rate on the properties of laser welded AM50 and AM60 magnesium alloys has been investigated. Butt welding without filler material was conducted on 3mm thick high pressure die cast (HPDC) plates using a high power Nd:YAG laser. All butt welds were produced at 2kW nominal laser power, 0.6mm diameter laser spot size and plate travel speed of 2.5m/min. Tensile testing of the parent HPDC alloys and welded samples was performed at three different strain rates ranging from 0.0016s-1 to 2s-1. For the welded samples, both longitudinal and transverse tensile tests were performed where the loading axis was parallel and perpendicular to the weld bead respectively. Results are presented and the effects of strain rate on the properties of the welded joints are discussed in this paper.The influence of strain rate on the properties of laser welded AM50 and AM60 magnesium alloys has been investigated. Butt welding without filler material was conducted on 3mm thick high pressure die cast (HPDC) plates using a high power Nd:YAG laser. All butt welds were produced at 2kW nominal laser power, 0.6mm diameter laser spot size and plate travel speed of 2.5m/min. Tensile testing of the parent HPDC alloys and welded samples was performed at three different strain rates ranging from 0.0016s-1 to 2s-1. For the welded samples, both longitudinal and transverse tensile tests were performed where the loading axis was parallel and perpendicular to the weld bead respectively. Results are presented and the effects of strain rate on the properties of the welded joints are discussed in this paper.
Metallurgical and Materials Transactions, Sep 14, 2017
Some types of anodes that could replace the usual carbon anodes in aluminium production by the Ha... more Some types of anodes that could replace the usual carbon anodes in aluminium production by the Hall-Heroult process are based on SnO 2. The present investigation deals with SnO 2-Sb 2 O 3-CuO ceramics having an SnO 2 content of 96%), Sb 2 O 3 and CuO being dopants. The ceramic pellets, thermally treated at 1400 C for 4 hours, were analysed by X-ray diffraction and IR spectroscopy. The structural analysis of the samples evidenced an SnO 2 (ss) type solid solution. All samples were electronically conductive (small negative values of the Seebeck coefficients), having an activation energy ranging within 0.02-0.3 eV. The anodic polarisation curves obtained with those anodes in an electrolyte of 88% Na 3 AlF 6 , 7% Al 2 O 3 and 5% CaF 2 were studied. The results were correlated with the microstructure of the investigated samples.
Pacific International Conference on Applications of Lasers and Optics, 2004
The feasibility of controlling dilution through on-line temperature control during continuous wav... more The feasibility of controlling dilution through on-line temperature control during continuous wave laser cladding of aluminium (Al) alloys has been investigated. A series of experiments was conducted at IRIS with a high power Nd:YAG laser using Al 7075-T6 substrates and an Al alloy powder containing 12wt% silicon (Al-12Si). The melt pool temperature was measured with a 2-colour optical pyrometer and on-line temperature control was performed by closed loop monitoring of the laser power using the TemCon© control software developed at LZH. Comparative cladding trials were performed with and without temperature control, as well as with and without cooling of the substrate. The effects of laser cladding condit ions such as the substrate scan rate, powder feed rate and track increment on clad dilution were determined by quantitative metallography. Results are described in this paper and the benefits of on-line temperature control are discussed.The feasibility of controlling dilution through on-line temperature control during continuous wave laser cladding of aluminium (Al) alloys has been investigated. A series of experiments was conducted at IRIS with a high power Nd:YAG laser using Al 7075-T6 substrates and an Al alloy powder containing 12wt% silicon (Al-12Si). The melt pool temperature was measured with a 2-colour optical pyrometer and on-line temperature control was performed by closed loop monitoring of the laser power using the TemCon© control software developed at LZH. Comparative cladding trials were performed with and without temperature control, as well as with and without cooling of the substrate. The effects of laser cladding condit ions such as the substrate scan rate, powder feed rate and track increment on clad dilution were determined by quantitative metallography. Results are described in this paper and the benefits of on-line temperature control are discussed.
Materials Science Forum, Jun 1, 2011
In the present study, surface melting of a magnesium alloy, ZE41, was performed with an Nd:YAG la... more In the present study, surface melting of a magnesium alloy, ZE41, was performed with an Nd:YAG laser, using different laser parameters (scan rate and beam type). The microstructure of the laser treated and untreated specimens were characterised by optical and scanning electron microscopy. The degree of microstructural refinement and melt depth was found to be a function of the laser scan rate. Electrochemical characterisation of the different laser treated specimens along with the untreated alloy was performed using electrochemical impedance spectroscopy. The laser treated specimens and untreated alloy showed similar corrosion resistance.
Applied Surface Science, Aug 1, 2010
Thermal barrier coatings (TBCs) are frequently used as insulation system for hot components in ga... more Thermal barrier coatings (TBCs) are frequently used as insulation system for hot components in gasturbine, combustors and power plant industries. The corrosive gases which come from combustion of low grade fuels can penetrate into the TBCs and reach the metallic components and bond coat and cause hot corrosion and erosion damage. Glazing the top coat by laser beam is advanced approach to seal TBCs surface. The laser beam has the advantage of forming a dense thin layer composed of micrograins. Plasmasprayed yttria-stabilized zirconia (YSZ) coating was glazed with Nd-YAG laser at different operating conditions. The surface morphologies, before and after laser treatment, were investigated by scanning electron microscopy. Laser beam assisted the densification of the surface by remelting a thin layer of the exposed surface. The laser glazing converted the rough surface of TBCs into smooth micron-size grains with size of 2-9 m and narrow grain boundaries. The glazed surfaces showed higher Vickers hardness compared to as-sprayed coatings. The results revealed that the hardness increases as the grain size decreases.
Magnesium alloys possess a combination of low specific weight and high specific strength that mak... more Magnesium alloys possess a combination of low specific weight and high specific strength that makes them attractive to a range of industries such as the automotive and aerospace. A hindrance to their greater application is their poor wear and corrosion resistance compared to that of steel or aluminium alloys. This is due to their relatively low surface hardness and high chemical affinity for numerous elements. This study investigates the microstructure and wear characteristics of clad layers made of a mixture of Al-12%Si (40%) and tungsten carbide (60%). The claddings were deposited on creep resistant AS21 magnesium alloy using a high power Nd:YAG laser.
Compared to conventional arc-welding processes commonly used to repair aluminium (AI) components,... more Compared to conventional arc-welding processes commonly used to repair aluminium (AI) components, laser cladding involves lower overall heat input) less part distortion and narrow heat affected zones (HAZ). With the development of high power lasers, it has become an attractive technology for the refurbishment of high value-added structural airframe components in commercial and military aircrafts, especially those made of hard-to~weJd heat treatable Al alloys. A series of cladding trials was performed on A17075-T6 alloy substrates using an AI-12Si alloy powder as the filler repair material because of its high corrosion resistance and a high power Nd:YAG laser. The effects of laser operating parameters such as laser power, substrate scan rate, powder feed rate and increment between cladding tracks on the clad characteristics, e.g. height, depth and dilution, were investigated. Results are described, showing how the process conditions were optimized to reduce the clad depth) dilution and HAZ, while minimizing the fonnation of porosity in the clad during solidification. C1ad samples were produced without liquation cracks in the HAZ, and despite the unavoidable formation of decorated grain boundaries near the fusion zone, the tensile strength of selected claddings was acceptable, within 5% ofthat of the parent metal, while ductility was low but similar to the parent metaL
ABSTRACT Magnesium alloys are of growing interest for a number of applications in a range of indu... more ABSTRACT Magnesium alloys are of growing interest for a number of applications in a range of industries because of their low densities and high specific strength. An impediment to their increased application is their low resistance to both wear and corrosion compared to that of steel or aluminium alloys. This is due to their relatively low surface hardness and high chemical affinity for numerous elements respectively. This paper describes the results of experiments investigating Nd:YAG laser cladding of AS21 magnesium alloy with a mixture of aluminium silicon (40 % wt) and tungsten carbide (60 % wt) powder to improve its wear properties. The effects of laser power, scan speed, powder feed rate, and laser spot size on the clad layer thickness were examined. The results indicate that crack and porosity free clad layers up to 2 mm thick can be produced under optimum laser and powder mass flow rate conditions
Journal of Materials Science & Technology, 2022
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Papers by Yvonne Durandet