Division of microstructure of surfaces and interfaces
Our division specializes in the microstructural analysis of metallic materials, particularly composite materials with a metal matrix prepared using the gas pressure infiltration method or 3D additive manufacturing. Our projects also involve studying metallurgical processes of welds prepared by dual laser beam welding or by CCDS. Additionally, we analyze the structures of various materials, such as steels, nanostructured materials, intermetallic alloys, and metal foams, prepared using different technologies like powder metallurgy, casting technology, or metal foaming, which are investigated at our institute. We observe and characterize materials at the macro level (light microscopy) or the micro level (electron microscopy). We can test materials to determine their chemical composition, thermophysical properties, and microhardness. We collaborate with industries to support structural analysis and material testing, conducting comprehensive studies on various practical issues. In our division, we have several laboratories.
Laboratory of metallography
We have a fully equipped metallographic laboratory available to prepare samples for microscopic observation. The samples are cut to the desired shape and pressed into thermoplastic or thermoset molding material for subsequent attachment to an automatic grinder/polisher or other sample preparation for analysis using microscopes, hardness testers, or spectrometers. We can polish the samples in a vibratory polisher or cross-section polisher for scanning electron observations. Samples for observation on a transmission electron microscope are precised polished by PIPS system or electrolytically.
Laboratory of microscopy
Microstructural analysis of materials has become indispensable for their research. We mainly use light microscopy to check the macrostructure of prepared metallic materials or welds. The use of a scanning electron microscope (SEM) is suitable for monitoring and characterizing the surface (textures) of metallic materials after technological operations, or the shape and size of powder particles, material fractures, analysis of fracture surfaces or cracks, chemical and phase composition, and the distribution of additive elements in the material after heat treatment or corrosion monitoring.
Our microscope infrastructure consists of two scanning and two transmission electron microscopes. The first scanning electron microscope with a tungsten cathode achieves a resolution of 3.0 nm (30 kV), 8 nm (3 kV), or 15 nm (1 kV) with a maximum magnification of 300,000x and an acceleration voltage range from 0.3 kV to 30 kV. It is suitable for sample sizes up to 50x50x50 mm and a weight of 100g. The second is a scanning electron microscope with a Schottky cathode for achieving a resolution of 1.0 nm (15 kV) or 1.5 nm (1 kV) with a maximum magnification of 1,000,000x and an acceleration voltage range from 0.1 kV to 30 kV. It provides multiple options for observing in secondary electrons (SE) using two SEI and LEI detectors. With high (BSE) and low-angle (LABE) backscattered electron detectors, it is possible to observe the distribution of elements or phases in the microstructure at high magnifications. It is also equipped with an energy-dispersive X-ray analyzer (EDS) Oxford Instruments X-max 50 mm2. A wavelength-dispersive analyzer (WDS) can be used on this microscope for more precise determination of chemical composition. Electron backscatter diffraction (EBSD) is used for studying the crystallographic orientation of grains in the microstructure of materials. It is suitable for sample sizes up to 50x50x35 mm and a weight of 50g.
The transmission electron microscope (TEM) is ideal for various applications, such as biological and materials research, nanotechnology, metallurgical processes, etc. It provides topographical, morphological, compositional, and crystalline information. The obtained information helps study crystals and metals and has industrial applications. It is necessary to confirm whether the material’s unique properties result from its structure. Images allow us to analyze the material’s structure at the nanostructure level. Electrons pass through the specimen, which is placed between the electron source and the condenser/CCD camera. Therefore, samples intended for TEM observation must be metallographically prepared to be as thin as possible (approximately 0.5μm or less). The high-resolution TEM with an X-FEG cathode is designed for advanced observations of diffractions and achieving resolution at acceleration voltages of 80, 200, and 300 kV. At 200 kV, the resolution is approximately 0.8Å. The microscope is equipped with an FEI CETA camera with a TEM detector – CMOS for observation in multiple STEM modes – HAADF, BF, DF2, DF4, and equipped with an EDX – Super X and EELS spectrometer for mapping the distribution of elements and atomic distribution. It is also equipped with a cryo holder.
Thermal Analysis Laboratory
The thermal analysis laboratory uses various measurement methods to analyze changes in the composition and properties of materials depending on temperature changes. In the dilatometry experimental method, we measure changes in the length of the examined material due to physical, chemical, or technological processes. We calculate the thermal expansion of materials, based on which we can determine the coefficient of thermal expansion (CTE) or various phase transformations. These changes are measured depending on temperature and time/duration at temperature. Methods like thermogravimetric analysis (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC) are used to study changes in mass, determine the thermal stability of substances and materials, thermal decomposition, determine the temperatures of phase transitions, melting or solidification, determine the purity of substances, and others. All our thermal analysis devices can measure samples in the temperature range from room temperature to 1600°C. Measurements are carried out in various atmospheres (vacuum, air/oxygen, inert gases, and mixtures).
Pressure Infiltration Laboratory
In the pressure infiltration laboratory, we focus on preparing composite materials using gas pressure infiltration technology and studying their structures, interfaces and overall properties. The gas pressure infiltration method makes it possible to prepare materials reinforced with fibers or particles and fill the microporous material’s pores with molten metal. This technology is fast and relatively cheap. We currently use three autoclaves, laboratory, medium and large, which differ in volume and technical parameters. On samples prepared in a laboratory autoclave, we study the interphase interaction of components and its influence on the resulting properties of composite materials. We focus on fibre-reinforced metal composites or microporous materials infiltrated with molten metal. The size of the samples that we can prepare in a laboratory autoclave is 10x10x50 mm. We can create an initial vacuum of 10 Pa in the autoclave. We can control the infiltration temperature range with an accuracy of +/- 1 °C up to 1150 °C. The maximum infiltration pressure is 6 MPa. The working volume of the chamber of the laboratory autoclave is 3 liters. We can prepare smaller parts of a complex shape, e.g., for industrial use, in a medium autoclave. The dimensions of the parts can be 60 mm in diameter or 80 mm in length. However, the cumulative volume of the part must not exceed 0.251 dm3. The maximum infiltration temperature is 1200 °C, and the maximum infiltration pressure is 5 MPa. The working volume of the autoclave chamber is 33 liters. A large autoclave enables small-scale production of larger parts with a complex shape. The dimensions of the parts can be 200 mm in diameter or 380 mm in length. However, the cumulative volume of the part must not exceed 8.3 mm3. The maximum infiltration temperature is 1300 °C, and the maximum infiltration pressure is 10 MPa. The working volume of the autoclave chamber is 380 liters.
Laboratory of 3D additive manufacture
Additive manufacturing (3D printing) at our division is centered on FDM (Fused Deposit Modeling) technology. As part of research projects, we work with developed and commercially available cartridges with metal and ceramic particles (316L, CuSn, Al2O3, and we also deal with 3D printing of various viscous materials (pastes, hydrogels, clays) that can be 3D printed with DIW (Direkt Ink Writing) technology.