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Microstructure and Properties Evaluation of Ductile Cast Iron Subjected to Hot Plastic Deformation and Ambient Temperature Compression

100%

Chaus A. S. , Čaplovič Ľ. , Pokrovskii A. I. , Sobota R.

tom Vol. 68, iss. 2

639--648

The as-cast microstructure of ductile cast iron (DI) was investigated using light microscopy (LM) and SEM techniques. Further the influence of hot plastic extrusion at 1000°C with plastic strain in the range of 20-60-80% on the transformation of the as-cast microstructure and on the mechanical properties was studied. Besides this, the microstructure of DI subjected to hot extrusion after the fracture of the corresponding samples induced by compression tests was thoroughly investigated. It was found that compression had a dramatic influence on a shear deformation and hence shear fracture of the compressed samples. It was shown that the shear fracture of the hot deformed ductile iron is accompanied by the occurrence of a narrow zone of severe plastic deformation. The fracture surfaces of the extruded samples subjected to the tensile tests and the compression tests were examined.

The importance of FEM simulation in design of a forming tool for test sample preparation to measure solder wettability

88%

Kapustova M. , Sobota R. , Kolenak R. , Bilik J. , Simna V.

Hutnik, Wiadomości Hutnicze

2019

tom Vol. 86, nr 8

253--256

The paper describes the construction design, simulation and preparation of a forming tool for manufacturing the ball-shaped test samples. This test sample shape is required for innovative evaluation of solder wettability, as the ball represents by its ideal shape a complete non-wettability of the substrate surface. The simulation software Deform was used for the FEM analysis of material flow in the tool cavity in order to verify the correctness of the forming tool design. After the successful computer simulation the designed forming tool was manufactured. The production of the ball-shaped test samples was successfully performed under laboratory conditions.

W artykule przedstawiono projekt, symulację i przygotowanie narzędzia kształtującego, które umożliwia wytwarzanie próbek w kształcie kuli. Tego typu próbki są wymagane przy innowacyjnym sposobie oceny zwilżalności lutu, gdyż kula dzięki swemu idealnemu kształtowi odzwierciedla całkowity brak zwilżalności powierzchni podłoża. Program symulacyjny Deform, który wykorzystano do przeprowadzenia analizy MES płynięcia materiału w wykroju narzędzia, umożliwił weryfikację poprawności projektu narzędzia kształtującego. Po przeprowadzonej symulacji komputerowej wytworzono zaprojektowane narzędzie kształtujące, które z powodzeniem zastosowano do produkcji próbek kulistych w warunkach laboratoryjnych.

Evaluation of the strength properties of materials intended for tracheobronchial tubes

75%

Sobota R. , Markowski J. , Joszko K. , Gzik-Zroska B. , Kawlewska E. , Gzik M.

Engineering of Biomaterials

2020

tom Vol. 23, no. 156

10--16

The desire to increase the comfort of patients and to continue production despite the decreasing amount of available materials on the market has led to the constant search for novel materials that could be used to obtain tracheobronchial tubes. The aim of this study is to determine the mechanical properties of a new thermoplastic elastomer. Two materials - the thermoplastic elastomer and the natural rubber were subjected to three tests: static tensile test, static compression test and static three-point bending test. During the static tensile test, samples of the tested materials were examined, and during the next two examinations, the final products. The materials underwent the processes of sterilization, hydrolytic degradation and degradation by oxidation. The treated samples were also tested in order to compare the obtained results. The mechanical properties of the tested materials improved both after the hydrolytic degradation and oxidative degradation, as well as after the sterilization process. Yet the thermoplastic elastomer revealed a more noticeable increase. The elastomer hardening is a positive phenomenon potentially leading to fewer accidental closures of the tubes cross-section. Both the sterilization process and various degradation methods improved the mechanical properties by strengthening the tested materials. This phenomenon seems to be desirable to avoid the closure of the implemented tube during its application.