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The proceedings of the 2nd konference of PhD students Multiscale design of advanced materials
Papers contributing to the solution of multilevel investigation and design of materials prepared either by members of doctorate team and PhD student investigating separately on the same institutions engaged in solution of doctorate project of Czech Science Foundation are contained in the proceedings. The contributions are oriented on theoretical and experimental aspects of materials designs arising form different approached from first principles up the continuum mechanics.
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Crack stability analysis of the crack in surface protective layers based on crack mouth opening displacement
Bareš, Pavel
Paper deals with stability analysis of a crack in a coating on a substrate. It is considered that the crack is perpendicularly oriented to the interface between the coating and the substrate and the crack tip lies directly on the material interface. The simple method based on crack mouth opening displacement parameter CMOD is proposed here for a critical stress calculation in the case of through coating crack in very thin coatings. The method is then applied herein on the model example and the critical stresses for different material combinations of the coating and the substrate are calculated. Note that under these stresses the crack will start propagate across the interface to the substrate. All calculations are performed by a finite element method FEM in the system ANSYS.
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Multiscale design of advanced materials
Král, L. ; Million, Bořivoj
In this paper, the results of measurements of chemical diffusion of Mn in steel weldments are reported. Chemical concetnration of Mn an interval 0-15 wt.% Mn was varied. Alloys were casted in induction furnace under protective Ar atmosphere. Diffusion couples were annealed at 800-1100°C for 96-1.5 hours respectively. Measurement of Mn redistribution was done in a normal direction to welding interface using scanning electron microscope Philips SEM-505WDS equipped with Microspec WDX-2A. Diffusion coefficients of Mn were obtained by fitting experimental curves to the known analytical solution.
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The structural and the fundamental mechanical properties of intermatallics on the base of TiAl
Krahula, Karel ; Dlouhý, Ivo
Gamma TiAl alloys are emerging as a pervasive structural material. Remarkable progresses have been made through refining lamellar microstructure and grains, microalloying, chemistry modification, process development and/or their combination. The main thrust was to enhance resistance to creep deformation, oxidation and high cycle fatigue deformation/failure. Less or even no knowledge have been obtained in the field of the intermetalics fracture at uniaxial or bending loading, there are missing data about their behaviour at the presence of cracks and other defects. The reason is simply in the other properties that are key from application point of view. Due to their brittleness at temperature close to room temperature the investigation of the intermetalics fracture is complicated but promissible provided it bring ideas for the further development of the alloying and microstructure. The paper is focused on the first steps in this field.
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Multiscale design of advanced materials
The proceedings of the 1st conference of PhD students Multiscale design of advanced materials organised in the frame and with financial support of doctoral project of Czech Science Foundation No. 106/05/H008.
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