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Information × Registration Number 0212U001542, 0110U004789 , R & D reports Title High-frequency fatigue of metallic glass investigations. popup.stage_title Head Bakai Aleksandr Stepanovich, Доктор фізико-математичних наук Registration Date 10-02-2012 Organization National Science Center "Kharkiv Institute of Physics and Technology popup.description2 As part of the project's first phase were carried out studies of the structure of bulk metallic glasses by high-resolution field emission microscopy. Studied the cluster structure of bulk metallic glass (BMG) Zr52.5Ti5Cu17.9Ni14.6Al10, r41Ti14Cu12, 5Ni10Be22, 5. In the quenched state revealed internal boundaries, whose density is 10^6 cm^-1. It is shown that the atoms in the intercluster boundaries are the binding energy decreased by 0.13 - 0.43 eV. Finding subclusters heterogeneity of the structure of bulk amorphous alloy with a characteristic scale of short-range order 1.5 - 3 nm show a plurality of short range order in glass-rozplavah. The effect of high frequency pretreatment on the strength and acoustic emission of bulk metallic glasses (BMG) based on zirconium: Zr52.5Ti5Cu17.9Ni14.6Al10, Zr46.25Cu45.25Al7.5Er1. To study the effect of ultrasonic treatment on structure and mechanical properties of the BMG was used the method of acoustic emission (AE). Kaiser effect, which was observed in the BMG evidence of the existence of stable extended defects in these materials. Reduction of AE activity and the strength of BMG after ultrasonic treatment suggests that the strength of BMG determined by the strength of intercluster boundaries, which restructured and "soften" the action of ultrasonic mechanical vibrations. To study the effect of ultrasonic treatment (UST) on the elastic properties and internal friction BMG depending on the temperature was first used by dynamic mechanical analysis (DMA). Established: UST for 5 minutes. leads to a decrease of Young's modulus at 5000-1000 MPa depending on the test temperature, the change in internal friction on temperature change, but its value increased slightly. As a result of UST for 15 min. elastic properties of the alloy decreased to 20 GPa. On the curve of internal friction peak appeared at 120 ° C. In comparison with the original alloy changed the dependence of internal friction on temperature and its value has grown substantially. To study the processes of transition of amorphous to crystalline state used simultaneous thermal analysis (STA). Estalished: UST of BMG (Zr55Cu30Al10Ni5) 99Y1 leads to its partial crystallization, which seen a decrease in the heat of crystallization during further heating of the samples and their oxidation; alloy treatment with ultrasound for 5 minutes. does not lead to noticeable changes in thermophysical parameters of crystallization of the samples during their heating, ultrasonic treatment for 15 min. reduces the glass transition temperature of fame at 15 ° C, reducing the crystallization temperature of 6 ° C zone of pseudo liquid state at the same time, respectively, increases by almost 10 ° C, resulting in a long voiceover alloy (15 min) the redistribution phase, which is reflected the DSC curves during solidification of alloys from the amorphous state and melt upon further heating; UST fame did not have a noticeable effect on the activation energy of crystallization of the alloy. Thus, we have investigated the nanostructure BMG different tracks and conditions, that the UST, even at relatively low amplitudes significantly affects the properties of the OMC: reduced strength and Young's modulus, is suppressed by the Kaiser effect, modified the temperature dependence of internal friction and relaxation kinetics. Product Description popup.authors Бакай Олександр Степанович Бакай Сергій Олександрович Петрусенко Юрій Тимофійович Щерецький Олександр Анатольйович popup.nrat_date 2020-04-02 Close