M. H. Robert

Magnetic and electrical properties of aluminium matrix composite reinforced with magnetic nano iron oxide (Fe3O4)

Abstract Aluminium matrix composite materials are used in aeronautical and aerospace, defence and automotive applications especially in the thermal management areas. Aluminium matrix composites (AMCs) reinforced with nano iron oxide (Fe3O4) exhibit good physical and mechanical behaviour (electrical conductivity and magnetic permeability), which makes them excellent multifunctional lightweight materials. The present paper is based on low-cost manufacturing of light and efficient materials for aeronautical applications. First of all, the results of dielectric spectroscopy are presented and space charge measurements are evaluated. To that end, a study has been carried out on an aluminium matrix composite reinforced with nano iron oxide and other alloying elements produced in our laboratory. Micro-indentation tests were conducted on the AMC to investigate its elastic modulus, hardness, and scratch tests with very long cycles were performed to study its wear performance. Scanning electron microscopy was used to study the morphology of damaged surfaces. The goal was to get more information about the influence of fillers on the corresponding reinforcing and wear mechanism.

Design and physical properties of multifunctional structural composites reinforced with nanoparticles for aeronautical applications

Abstract The multifunctional structural composites (MSCs) are used in engineering applications mainly in the aeronautical area because they meet the necessary requirements in new multifunctional systems. These composites exhibit good overall mechanical and thermal performance and potentially offer a large variety of functional properties. The present paper discusses the design, manufacturing and characterisation of these multifunctional structural composites. Generally, a combination of structural and energetic functions is achieved using different nanoparticle reinforcements in epoxy–rubber composites This type of material design gives an exigent task to the designers looking to integrate more functionality into the base material of their structure to achieve overall improved system performance. This paper is focused on the design of MSCs reinforced with Ni + Al mixture with Fe304 nanopowders in different ratios in a matrix of epoxy – fresh scrap rubber. We expect this material would be attractive for industrial applications because of the readily available recycled materials that are utilised. The mechanical and some physical properties of these composite systems were studied in this research. Microstructural characterisation revealed that micro- and nano-sized reinforcements were dispersed homogeneously in the epoxy–rubber matrix. Magnetic properties and surface wear resistance have been evaluated in detail as a function of the microstructure obtained for different compositions.

New magnetic aluminum matrix composites (Al-Zn-Si) reinforced with nano magnetic Fe3O4 for aeronautical applications

Abstract Aluminum metal matrix composites (AMMCs) are light-weight materials are widely used in structural applications due to their favorable properties such as lightweight, high specific strength and modulus, wear resistance and low coefficient of thermal expansion. Today, new developed magnetic aluminium based composites (Al-Zn-Si) became very attractive due to their improved magnetic, physical and mechanical properties. These composites, depending on final desired properties with different reinforcement types, are very suitable for electrical motors and other usage in aircraft engineering. These promising properties of AMMCs are attributed to the size and distribution of the reinforcement, as well as to the grain size of the matrix. Process that was used in this work is called ‘Sinter-Forging’ during which compacted aluminium specimens were forged just after sintering. A novel near-net shape, low-cost sinter-forging approach to processing particle-reinforced metal matrix composites allow manufacturing parts for high performance applications with short processing time and low energy consumption. The aim of this work is to briefly present the efficient ‘Sinter-Forging Process’ and to summarize properties of new composites developed for aeronautical applications.

Design of Al-Nb2Al Composites Through Powder Metallurgy

The present study deals with a new design of aluminum alloy based composites reinforced with Nb2Al particles and Glass Bubbles (GB) through powder metallurgy. The matrix for these composites was chosen as 1050 pure aluminum alloy powder. The composites were produced under solid state-liquid state sintering conditions to improve the interface between Nb2Al and the aluminum matrix. Processing parameters were optimized and products were analyzed as a function of the content of reinforcing particles in the matrix, as their interfaces with matrix, etc. Mechanical properties were evaluated by means of compression tests. General results show the feasibility of producing composites by the proposed route economically. Products with good mechanical properties could be obtained. The process gives a new opportunity for the production of a novel material from recycled wastes. Microstructural evaluations were made by Optical and Scanning Electron Microscopes.

Design of Magnetic Aluminium (AA356) Composites (AMCs) Reinforced with Nano Fe 3 O 4 , and Recycled Nickel: Copper Particles

New classes of aluminium matrix composites (AMCs – 356) were designed by three different manufacturing techniques; only sintering, through combined method called here after “Sinter + Forging” and/or “sinter + thixoforming”. Main reinforcement was magnetic iron oxide, Fe3O4 (10, 20 and 30 wt %) and two recycled reinforcements, nickel, Ni and pure electrolytic copper, Cu, given by French Aeronautical Society were also used and preceded under the constant process parameters such as hot compaction, sinter-forging, sintering time, Forging temperature and Force, etc. As auxiliary element, hybrid graphene nano-platelets, GNPs, was added in the structure. Microstructural analyses (by using SEM), magnetic, mechanical and physical properties of the composites were compared with three different manufacturing processes. Static compression tests, Micro hardness tests, measurement of magnetic permeability and also electrical conductivity, have shown that the mechanical and physical properties of these composites can be improved with the optimization of process parameters. In the present work, an alternative and a low cost manufacturing process were proposed for these composites.

Design of Magnetic Aluminium (A356) Based Composites through Combined 2 Method of Sinter + Forging 3

In this work, aluminium matrix composites (AMCs with scrap A356 powder given by French Aeronautical Society) were designed through combined method of powder metallurgy and thixoforming (sinter + Forging). Three different reinforcements (Magnetic iron oxide, Fe3O4 – Hybrid graphene nano-platelets, GNPs, Nickel, Ni) were used and preceded under the constant process parameters such as hot compaction, sinter-forging, sintering time, etc. Mechanical and physical properties of the composites were improved with the combined processing method of powder compacted specimens and reinforcement volume fractions. Static compression tests, Microhardness tests, surface scratch tests, measurement of magnetic permeability showed that the mechanical and physical properties of these composites can be improved with the optimization of process parameters. In the present work, an alternative and a low cost manufacturing process were proposed for these composites. The microstructure and damage analyses have been carried out by Scanning Electron Microscope (SEM).

Recycle of Aluminium (A356) for Processing of New Composites Reinforced with Magnetic Nano Iron Oxide and Molybdenum

The microstructural and tribological behavior of Aluminium Matrix Composites (AMCs with scrap A356) reinforced with nano iron oxide (Fe3O4) and Molybdenum (Mo) produced by powder metallurgy was investigated with low cost manufacturing of light and efficient multifunctional materials for aeronautical applications. Molybdenum (Mo) is a refractory material with a high melting temperature and used essentially as high-temperature resistant materials for applications in the fields of aerospace engineering such as rocket nozzles, high-temperature resistant pieces, etc. It shows a low thermal expansion coefficient, excellent electrical conductivity and higher corrosion resistance. However, it becomes very brittle after recrystallization. Generally, AMCs reinforced with magnetic iron (Fe3O4) exhibit good physical (electrical and magnetic) properties, which make them excellent multifunctional lightweight materials.

Particles Reinforced Scrap Aluminum Based Composites by Combined Processing Sintering + Thixoforging

Scrap aluminium (AA 7075) chips are recycled for new composite design through combined method of powder metallurgy and thixoforging as a more economic method. Thixoforging processing is already known as low cost manufacturing of the structural materials. In this work, we have used an additional route (powder metallurgy) to facilitate the thixoforging processing. This new approach can help for improving performance and efficiency of the processing. AA7075 Aluminium chips are used as matrix and boron is used as main reinforcement element and others such as BN, TiO2, graphite, and spherical ceramics are used as minor reinforcements, respectively. Graphite powders are added for their good lubrication and improving damping behavior. Microstructure, mechanical properties and Impact performance are compared depending on the reinforcement elements.

Aluminium Matrix Composites Reinforced by Nano Fe 3 O 4 Doped with TiO 2 by Thermomechanical Process

In this work, scrap Aluminium Matrix Composites (AMCs) reinforced with 10 wt% nano iron oxide (Fe3O4) were produced and the influence of doping Fe3O4 with TiO2 at 2.5 %, 5 %, 7.5 % and 10 % wt%, was studied. For the dispersion of the reinforcement and the study of the matrix/reinforcement, interface was evaluated by Scanning Electron Microscopy (SEM). Density and microhardness of the composites were measured and compared. Wear and creep response of the composites were evaluated by a nanoindenter, Furthermore modulus and hardness of the composites were calculated using the unloading data from the nanoindentation tests. Relatively homogenous distribution of the constituents, with a good bond between matrix and the reinforcements was observed. It was also observed that wear behaviour improved with the increase in the TiO2 content.

Manufacturing of Low Cost Composites with Porous Structures from Scrap Aluminium (AA2014) Chips

In this study, aluminium matrix composites, (AMCs) have been created with porous structures reinforced with brown sugar, BN, graphite powders, boron and also fine glass bubbles. These composites are produced as sponge structures with low thermal and electrical conductivity. The process comprises a simple mixture of aluminium powders obtained from scrap aluminium chips (A2014) and glass bubbles with fresh scrap organic sugar coming from the excess of the production and their blending and finally followed by compacting of the mixture. Addition of the wax is variable from 0 up to 10 %. Sintering is carried out in two steps. First of all, the green compact is heated to eliminate entirely the sugar after that classical sintering of the structure is made under the inert atmosphere. Glass bubbles added at the beginning of the green compact create a net of interconnected porosity. Basically, drop weight test were applied to measure the impact behaviour of these sponge composites and acoustic emission capacity was measured. Microstructural and fracture behaviour were evaluated by Scanning Electron Microscopy (SEM).