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Metal-ceramic functionally graded materials – manufacturing, characterization, application

Chmielewski M., Pietrzak K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 1

151--160

EN

Functionally graded materials (FGMs) belong to a new, continuously developing group of materials, finding application in various branches of industry. The idea of freely designing their construction profile, restricted only by the available manufacturing techniques, enables obtaining materials with composition and structure gradients having unprecedented properties. In this paper, selected results of works carried out by the authors and relating to the application of the developed metal-ceramic composites were presented in order to manufacture functionally graded materials for target purposes. Gradient structures with various construction profiles that can play different roles were produced on the basis on the following material pairs: Cr-Al2O3, NiAl-Al2O3 and Cu-AlN. Manufacturing conditions, microstructure characteristics and selected properties, crucial from the point of view of future applications, were presented.

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Tin-Copper-Lead Alloy Produced by Horizontal Centrifugal Casting

Vahdat S. E.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 1

131--137

EN

Horizontal centrifugal casting is an effective method for the production of hollow metal with good mechanical properties, low defect, cast to size and relatively cheap. The ability of a metal to satisfy the above requirements highly depends on its microstructure. In this study, the relationship between microstructural parameters such as grain size and the amount of phases with bulk hardness of SnCu4Pb3 is concerned in three areas of the product. Consequently, to achieve the desired hardness of the product in a particular area, the interaction of two factors of the microstructure including, grain size and particles amount of the hard intermetallic compositions (Cu6Sn5) should be noted.

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On the stress free deformation of linear FGM interface under constant temperature

Ganczarski A., Szubartowski D.

Acta Mechanica et Automatica

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2015

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Vol. 9, no. 3

135--139

EN

This paper demonstrates the stress free thermo-elastic problem of the FGM thick plate. Existence of such a purely thermal deformation is proved in two ways. First proof is based on application of the Iljushin thermo-elastic potential to displacement type system of equations. This reduces 3D problem to the plane stress state problem. Next it is shown that the unique solution fulfils conditions of simultaneous constant temperature and linear gradation of thermal expansion coefficient. Second proof is based directly on stress type system of equations which straightforwardly reduces to compatibility equations for purely thermal deformation. This occurs if only stress field is homogeneous in domain and at boundary. Finally an example of application to an engineering problem is presented.

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Functionally graded cermets

Jaworska L., Rozmus M., Królicka B., Twardowska A.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

73--76

EN

Purpose: Cermets have very good plasticity and high hardness. Functionally graded cermets secure obtaining of cutting tools with hard wear resistance surface layer and ductile body frame. A new FGM was obtained using P/M method. Design/methodology/approach: Materials were obtained using free sintering at vacuum and the high temperature-high pressure sintering method. Functionally graded cermets have more amount of hard phase in the surface layer and lower participation of this phase in the body frame. FGMs were prepared by the layers pressing method and the centrifugal deposition method. Findings: Material with 55 wt.% of TiC and 45 wt.% of (Ni,Mo) was prepared. The phase’s composition of this material was analysed. The ring structure of material and complex carbides formation was confirmed. The gradient of the phase composition and hardness measurement are presented. Phase composition of FGM strongly depend on conditions of centrifugal sedimentation process: duration, rotation speed, solid content, dispersive liquids. The centrifugal deposition process of powders forming guarantees gradient phase composition for materials obtaining the powder metallurgy methods. The FGM obtained by powders forming method should be sintered using pressure processes in a closed containers (or special assembly) because of materials high porosity which is a result of various chemical contents of this same material parts. Practical implications: Due to their low chemical affinity to steel and the resistance for high temperatures oxidation, cermets have better cutting properties than carbides. Application of cermet inserts guarantees the high quality of machined surface (low roughness). Cermets could be used in “dry cutting” processes. Originality/value: The centrifugal deposition method for powders with phases content gradient forming is original value.