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Titanium based alloys are increasingly used in biomedicine due to their favourable properties. However, because of their high cost, new methods are being developed to produce more economical alloys. Therefore, in the framework of this work, Ti-20Nb alloy was produced by powder metallurgy. Namely, experimental alloy was prepared by mechanical alloying in a ball mill. The samples were singled out from the powder mixture and pressed on a hydraulic press. Sintering was carried out in a tube furnace in an argon atmosphere. Different processing parameters regarding the time and temperature of sintering were applied. Chemical homogeneity was analysed using the energy-dispersive spectrometry. Porosity was observed using the light microscope and microhardness was determined by Vickers method. The obtained results show that with a small correction of the applied technological parameters, in terms of time extension of mixing/mechanical alloying, it is possible to produce economically Ti-20Nb alloy having the properties suitable for biomedical application by using powder metallurgy technology.

In this paper, thermomechanical processing of niobium microalloyed steel was performed with the purpose of determining the interaction between niobium precipitates and dislocations, as well as determining the influence of the temperature of final deformation on the degree of precipitation and dislocation density. Two variants of thermomechanical processing with different final rolling temperatures were carried out. Samples were studied using electrochemical isolation with an atomic absorption spectrometer, transmission electron microscopy, X-ray diffraction analysis, and universal tensile testing with a thermographic camera. The results show that the increase in the density of dislocations before the onset of intense precipitation is insignificant because the recrystallization process takes place simultaneously. It increases with the onset of strain-induced precipitation. In this paper, it is shown that niobium precipitates determine the density of dislocations. The appearance of L&uuml, ders bands was noticed as a consequence of the interaction between niobium precipitates and dislocations during the subsequent cold deformation. In both variants of the industrial process performed on the cold deformed strip, L&uuml, ders bands appeared.

This paper presents the results of testing the corrosion behaviour of K110 tool steel for cold work in industrial emulsion medium (Lenox Band- Ade semi-synthetic oil + water, in a ratio of 1:10), water and 3.5% NaCl medium. Using the method of electrochemical impedance spectroscopy (EIS) and Tafel extrapolation, electrochemical measurements were performed in order to determine the corrosion parameters. After polarization measurements, the surface of the sample was examined with an optical microscope. Tafel extrapolation of the polarization curves revealed that the tested tool steel showed the lowest corrosion rate in the Lenox Band-Ade emulsion medium and the highest in the medium of 3.5% NaCl. The obtained results were confirmed by the method of electrochemical impedance spectroscopy, where the lowest charge transfer resistance was registered in the 3.5% NaCl medium, which indicates the fact that the thinnest oxide layer was formed in tested medium, which has a very weak protective role in the corrosion process. Metallographic analysis of the sample surface after polarization measurements in 3.5% NaCl medium indicates the occurrence of pitting corrosion caused by the action of aggressive chloride ions from the solution, which caused the destruction an already weak passive layer on the metal surface. At the same time, chloride ions from the acid medium attack more aggressively the matrix of the metal base of the tool steel, in contrast to the precipitated carbides on the sample surface.