J. Grabian

An Application of Computer Tomography for Structure Characterization of Metallic-Ceramic Composite Foam

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.

Metal-Ceramic Composite Foams and their Fire Resistance

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).

Crystallisation of Silicon on Reinforcement Fibres as a Consequence of Overheating of Matrix Metal during Saturation in MMC

Metal-matrix composites for many years have been widely used as engineering material all over the world, also in Poland. It is due to good construction properties, small specific gravity, ease of product formation, also large size items, diversity of manufacturing methods, and great possibilities of changing their properties depending on the output products used [. The authors of this study deal with metal-matrix composites made by casting. One of the methods they use in their research includes the saturation of the reinforcement structure (short disordered fibres pressed like felt, forming a profile, called preform) with metal liquid matrix under pressure. Phenomena occurring in the production of a composite material are similar to those taking place during making casts from traditional materials (cast steel, cast iron, non-ferrous metal alloys). This article is an overview of a problem encountered while detecting and describing defects of metal-matrix composite materials produced by saturation. It focuses on phenomena that take place during casting solidificationespecially the influence of the matrix (with different temperatures of liquid metal) on the reinforcement during its saturation and crystallisation of silicon plates on it.