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Degradation processes occurring in materials of structural parts and technological units exposed to mechanical stresses, high temperatures, aggressive environment, radiation, etc. during operation can cause serious operational accidents leading to significant economic and ecological damage, possibly even loss of life. The research of these processes and fractographic analysis of damaged parts is one of the main activities of the Fractographic Department of the Department of Materials (KMAT) of Faculty of Nuclear Sciences and Physical Engineering (FJFI), which is celebrating 50 years of its existence. The anniversary celebration will take place in the FJFI building at Trojanova 13, Prague 2 on Thursday, 19 January 2023, from 13:00.

"In the Czech Republic, our cooperation is mainly focused on the aerospace, energy, transport and engineering industries. An important part of our work is also the research of breaking processes of newly developed materials, for example, hot-dipped coatings. Over the years, however, we have cooperated, among others, with the Assay Office, Faculty of Medicine of Charles University, or Metropolitan Chapter of the Cathedral of St. Vitus, Wenceslas and Vojtech, for which we analysed the damage of the Zikmund Bell," says doc. Jan Siegl from KMAT, who heads the Fraktography Department.

The CTU fractographic workplace has been included among the unique CTU scientific workplaces on the basis of the results achieved and responses at home and abroad. The results of fractographic analyses associated with experimental demonstration of fatigue life of airframes of Aero L29, L39MS, L159 or Flight L410 UVP aircraft were a significant contribution. In the field of nuclear power engineering, this department has participated in experimental studies of the influence of temperature and environment on the kinetics of crack propagation in materials used for the production of nuclear power plant components, e.g. for the French company Électricité de France or for the Joint Research Centre of the European Commission in Petten, the Netherlands. The fractographic department also carries out expertise aimed at the analysis of the causes and progression of operational failures of various parts of power equipment, especially turbine blades, pipelines, steam generators and others. This work is carried out on the basis of requests from both power plant operators and technology manufacturers and suppliers.

The FJFI fractographic department was founded by Prof. Ivan Nedbal in 1973, it was one of the first departments of this specialization not only at CTU but also at other universities in Czechoslovakia. The first line electron microscope at CTU - JEOL JSM 50A - was installed and operated at this department. Currently, the department uses three line electron microscopes from JEOL - JSM 840A (since 1988), JSM 5510LV (since 2002) and since 2018 - JSM IT500HR. During its existence, thousands of samples have passed through the department and almost 200 thousand images have been created and processed. "These are partly orders for industrial partners, but a large part is also scientific work focused on basic research and, of course, the work of our students. We have also created and are still adding to the Fractographic Atlas, which documents the characteristic features of fracture surfaces typical of the various failure mechanisms of the materials studied," explains doc. Jan Siegl.

Although the specialised fractographic department of CTU celebrates its 50th anniversary, the first written references in the field date back to the 16th century. In 1556, for example, Georgius Agricola in his book De Re Metallica described the malleability of iron based on the appearance (character) of the fracture surface. The microscope was first used to evaluate metal fractures in 1722 by René-Antoine Ferchault de Réaumur. The significant growth in the importance of fractography in the second half of the 20th century was mainly due to the extensive development of industry and the increasing demands for safety and reliability in the operation of manufactured machinery and equipment. The development of fractographic methods has been linked to the development of new experimental techniques and in particular to scanning electron microscopy.

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