Papers by Keyword: Metal-Ceramic Composites

Abstract: Properties of an interpenetrating metal–ceramic composite with freeze-cast preforms are investigated. For the estimation of elastic properties of the composite numerical homogenization approaches for 2D and 3D finite element models are implemented. The FE models are created based on micro-computed tomography (μCT) images. The results of the numerical 2D and 3D modeling coincide and are in good agreement with available experimental measurements of elastic properties.

Abstract: Authors of the paper present structures of composite metallic-ceramic foams (Al11SiC) of characteristic internal composition, produced at Maritime University of Szczecin. Diversification of pore size and structure of composite walls is present. The foams are manufactured by injection of a gas into a liquid composite using a special device, which allows to realize the foam manufacturing process in a continuous manner. This device also allows to control the parameters of the foaming process, which results in possibility of influencing, among other things, the size and the size distribution of formed gas bubbles. After manufacturing foams with both homogeneous and diversified gas pores, basic mechanical properties of these foams were examined, revealing a connection with their structure. Possibilities of applied research methods, utilizing a microscope and a tomograph, were also presented. Methods using computer image analysis were selected for the structure description.

Abstract: The development of aviation and outer space technologies necessitated working out new materials, resistant to increased temperatures, and satisfying specific requirements concerning high strength and low density. These requirements are met by metal composite materials produced by proper joining of the matrix (aluminium or magnesium alloys) and reinforcement components, mostly ceramic fibres, particles or whiskers. Such composite materials combine properties that traditional materials cannot yield. This contribution presents the method of composite foam production (SiC reinforcement, aluminium alloy matrix) by the mechanical method and testing of non-combustibility of these materials in accordance to the international FTP Code and the testing procedure PB-KTZ-01 (equivalent of ISO 1182).

Abstract: Metal-Ceramic Composites with high volume fraction of reinforcement find wide applications in the area of tribology and high temperature resistant components like piston, brake pads, heat shields etc. Most of these components can be made by infiltration processing of porous ceramic preforms. The present investigation is to synthesize porous ceramic preform based on SiC particles using inorganic salt as a pore forming agent and Squeeze infiltration is applied to fabricate the Al-SiC metal-ceramic composites. The direct squeeze infiltration of 6061 aluminum alloy on SiC preform is successfully carried out with the controlled process parameters of initial preform temperature, liquid metal superheat, squeeze pressure and its rate of application, and die temperature. The preform and composites are characterized using XRD, optical microscopy, electron microscopy, and hardness and compression strength. Porous ceramic preform with more than 50% porosity has been fabricated by sodium chloride as pore former. The infiltrated composite have shown uniform and complete infiltration of Aluminium alloy in between SiC particles and posses very high hardness of 147 BHN in as cast condition compared to 57 BHN for the 6061 Al alloy.

Abstract: A new class of metal/ceramic composites has recently been developed. A porous ceramic preform, the pore structure of which is created via a freeze-casting technique, is melt-infiltrated with metallic alloy via sqzeeze-casting. The microstructure of the composite has lamellar-like domains with geometrical characteristics which are dependent on the manufacturing parameters. The aim of our study is to find a good micromechanical model in order to deduce the mechanical properties of the single domains and of the whole material as a function of the microstructural geometry and the material parameters of the ceramics (alumina) and the alloy (Al-Si eutectic). Firstly, the statistical analysis of polarized light microscopic micrographs of the cross section of the specimen was performed. Domains with the same orientation of lamellae, so-called single domains were detected, selected and measured. The material modeling was performed by a two-step homogenisation procedure using a combination of different micromechanical models. Predicted material properties were compared with ultrasonic measurements for a single domain and for the whole microstructure.