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Information × Registration Number 0212U000322, 0111U007047 , R & D reports Title Experimental investigation of stability and mechanical properties of nanocrystalline titanium obtained by cryo-mecanical treatment. popup.stage_title Head Yagotyntsev Kostyantyn Olexandrovich, Registration Date 01-02-2012 Organization B.Verkin Institute for Low Temperature Physics and Engineering of National Academy of Science of Ukraine popup.description2 The experiments on tension, microindentation as well as acoustic studies of nanostructured titanium produced by the cryorolling method were done. It is established that the decrease of the grain size to 35 nm, due to cryorolling leads to a significant increase in the amount of grain boundaries and leads to strength increase (almost 3-fold) accompanied by plasticity reduction in the entire investigated temperature range 5 - 423 K. With deformation degree increase at cryorolling from e = - 1.3 to -2.3 the proportion of grain boundaries increases. In such samples the large grains with sizes up to 100 nm appeared, resulting in less homogeneous samples structure. At the same time no substantial increase in yield strength and plastic limits were observed. When the temperature is lowered from 300 K to 77 K, the microhardness of the samples increases by 70%, this indicates the thermally activated character of the plastic deformation in these materials. Based on the data obtained from microhardness temperature dependence the activation volume and activation energy which characterize the plastic deformation processes of nanostructured and submicron titanium were evaluated. The temperature dependence of the decrement of nanostructured samples at the oscillation frequency f = 80 kHz revealed a well-defined peaks of internal friction with temperature localization of T= 220 and 235 K, while in the initial sample the peak had a bimodal structure. Peak shift towards higher temperatures with increasing frequency of oscillation indicates thermally activated nature of the relaxation processes. Product Description popup.authors Ватажук Олена Миколаївна Легченкова Ірина Валеріївна Русакова Ганна Вікторівна Смолянець Руслан Володимирович Яготинцев Костянтин Олександрович popup.nrat_date 2020-04-02 Close