No abstract

Metal foams are a new class of materials with low densities and novel physical, mechanical, thermal, electrical, and acoustic properties. Aluminum foams especially show potential for use in lightweight structures, for energy absorption, and for thermal management. Open cell aluminum foams with tailored porous morphology were synthesized by a space-holder method. In these foams, the pore shape is predominantly controlled by the initial shape of the space-holder particles that are used to produce the preform. In this study, resin bonded sand and gypsum bonded ceramic space holder particles are used in the open cell foam production. This paper describes the space-holder method for manufacturing open cell aluminum foams and characterizes the density as well as the compressive property of the foams.

Si3N4 based composites containing different amounts of SiC and SiAlON were produced by reactive spark plasma sintering of Si3N4, SiO2 and C black. Y2O3 and AlN were added as sintering additives. The SPS process was carried out at sintering temperature of 1650 0C for 5 min with uniaxial pressure of 40 MPa in a nitrogen atmosphere.The mechanic properties and morphology of Si3N4 ceramic composite were determined. Microstructures of the sintered samples were observed by SEM images and phase compositions were analysed by XRD.

Si3N4 ceramics reinforced with SiC particles were fabricated via spark plasma sintering at 1650°C under 40 MPa pressure. AlN and Y2O3 were used as sintering additives. The purpose of this work was to study the influence of SiC powders on the properties of Si3N4/SiC composites. The microstructure, phase composition, and mechanical properties of the composites were investigated. It was found that mechanical properties of the composites improved, the α–β transformation and grain growth of β-Si3N4 were inhibited and the equiaxed grain increased due to the increase of SiC(w).

Metallic foams represent materials with low densities as well as good physical, mechanical, thermal, and electrical properties. Since they have pores, metal foams have a set of unusual properties compared with bulk structural materials, i. e. the can offer a unique combination of several properties that can not be obtained in one conventional material at the same time. Metal foams can be produced by different processing technologies and many of them are still under development. The lost foam technique is an alternative foundry process as compared to other conventional techniques. This paper reports about a new approach for the production of open-cell aluminium foam metal by such casting procedure. During the process, an expanded polystyrene cell has been used for pattern making and all critical steps for manufacturing open-cell metal foam by the new technique are described in detail.