Вісники та науково-технічні збірники, журнали
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Item Simulation and analytical studies of chip formation processes in the cutting zone of titanium alloys(Видавництво Львівської політехніки, 2023-02-28) Stupnytskyy, Vadym; She, Xianning; Dragašius, Egidijus; Baskutis, Saulius; Prodanchuk, Oleh; Lviv Polytechnic National University; Kaunas University of TechnologyThe low machinability of titanium alloys is determined by the physical, mechanical, and chemical properties of these materials and their mechanical characteristics. It is also evident in the hardened state of the material being processed during cutting and in the initial state. This phenomenon is caused by thermodynamic parameters that determine the properties of titanium material at elevated temperatures. The peculiarities of the cutting and chip formation processes during titanium alloy machining are presented in this article. The peculiarity of the described approach is the analysis of the results of simulation modeling of cutting in Deform 2D software. It is proved that the frictional factor in the formation of the thermal characteristics of the cutting process, which arises as a result of the chip sliding along the tool, dominates the load factor (caused by force and deformation processes in the chip root). It has been established that the length of contact between the chips and the tool’s rake face has a certain tendency to change: the contact length first increases and then decreases with increasing cutting speed. An analysis of the dependence of the chip compression ratio on changes in cutting speed has shown that with an increase in cutting speed, the average value of the compression ratio practically does not change, but the amplitude of its oscillation increases significantly, which is equivalent to a change in the shear angle. This parameter changes dynamically due to the adiabatic nature of chip formation.Item Kinetics of high-temperature interaction of titanium alloys with a carbon-containing gaseous medium(Lviv Politechnic Publishing House, 2018-01-29) Trush, Vasyl; Luk’yanenko, Alexander; Karpenko Physico-Mechanical institute of the NAS of UkraineDue to their excellent complex of physical, chemical, and mechanical properties, titanium alloys are unique materials for many branches of industry. An important feature of titanium is its high reactivity concerning the interstitial chemical elements (oxygen, nitrogen, and carbon). The absorption of interstitial elements by titanium alloys causes change in physical and mechanical properties of alloys and articles which are made of them. It should be noted that the titanium alloys are classified, in particular, by the compositions of their structures. Investigations of titanium alloys of different structural compositions will enable us to take into account the influence of their features on the kinetics of their interaction with interstitial elements. Results of experimental investigations of the influence of a carbon-containing gaseous medium on the kinetics of interaction of titanium alloys of different structural classes (α-, pseudo-α, and (α+β)) are presented in this paper. It is established that the interaction at high temperatures (T = 750–850 °C) of titanium alloys with rarefied carbon-containing gaseous medium (Ar+16.7 % C3H8) under a pressure of P = 0.116 Pa leads to the increase in mass of the specimens according to a law which is close to linear dependence on time.