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In order to improve the hold and function of dentures for the patient, various prostheses made of metal, mostly metal alloys, are used every day in dental practise. Cobalt-chromium alloys are usually the first choice because they have very good mechanical properties and satisfactory clinical conditions. Nowadays, laser welding is increasingly used in dental practise due to its numerous advantages over other technologies. In this work, therefore, six commercially available Co-Cr alloys were investigated. Three of them are used for metal-ceramic work, two for denture frameworks and one is suitable for both applications. They were joined by laser welding and subsequently analysed microscopically. Their mechanical properties were determined and statistically evaluated. The microhardness of the laser-welded alloys is in the range of 282–465 MPa in the weld zone and between 283 and 435 MPa in the heat-affected zone. The flexural strength of the laser-welded alloys is lower than the control group, but an alloy for the metal-ceramic work (I-BOND NF) shows very similar value. Furthermore, this alloy, together with two other metal-ceramic alloys, survived a maximum of cycles in dynamic tests. It was found that the laser method can be used for joining Co-Cr alloys while ensuring appropriate parameters that guarantee the quality of the dental work.

The influence of boron carbide and tungsten carbide on the apparent porosity, density, coercive force, hardness and microstructure of metal matrix composite of the Ferro-TiC type, is presented in this paper. The samples of investigated steel/titanium carbide composite were produced by powder metallurgy process, i.e. by powders mixing and compacting followed by sintering in the vacuum furnace. According to the results, steel/titanium carbide composite materials with addition up to 11.9 vol.% of boron carbide are interesting to detailed investigation as well as materials having more than 17.2 vol.% of tungsten carbide because these compositions show significant changes in hardness and coercive force values.

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 Lüders 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, Lüders bands appeared.