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Information × Registration Number 0223U001755, 0120U100214 , R & D reports Title The main regularities and physical nature of relaxation processes in hexagonal magnesium and zirconium polycrystals popup.stage_title Head Tkachenko Volodymyr H., Доктор фізико-математичних наук Registration Date 02-02-2023 Organization Institute of Problems of Materials Science named after IM Frantsevich of the National Academy of Sciences of Ukraine popup.description2  The object of research is the effect of alloying and modification of magnesium and zirconium and their alloys on their damping capicity and relaxation stability. The purpose of the work is to develop the physical foundations of the formation of resistance to dislocation microfluidity/creep, long-term strength based on modern concepts of elastic stress relaxation and structural (dislocation) relaxation in metal crystals with low symmetry of the crystal lattice, as well as the creation of metal alloy systems with a high level of elastic energy absorption (damping). Mechanisms of relaxation and damping in the systems of Mg-Al, Si, Ce and Zr-Nb-Sn-Mo alloys in a wide range of temperatures and deformation amplitudes have been established. In the region of small deformations (10-5–10-3), the dissipation of elastic energy in magnesium alloys has a dislocation nature in particular. It is shown that Si additives increase the level of damping by 35% compared to pure Mg, and Ce doping extends the range of relaxation stability of the alloy up to 300°С. At deformations >10-3, high damping properties of magnesium alloys are provided due to elastic twinning-detwining processes. A new model is proposed that describes the dynamics of twinning in magnesium and its alloys and, on this basis, an alloy in the Mg-Al-Si system with a high level of mechanical energy dissipation. The mechanisms of relaxation based on stress jumps method in zirconium in the range of 20–700 °С have been established. On this basis, a new promising dispersion-strengthened Zr-1Nb-3Sn-1Mo alloy is proposed, which is 2 times more heat-resistant at 400 °С (YS ≈ 609 MPa and UTS ≈ 734 MPa) compared to industrial nanodispersion-strengthened zirconium alloys (YS≈ 270 MPa and UTS ≈ 348 MPa). Moreover, this alloy at 500 °C has significantly higher creep resistance than known industrial zirconium alloys at 400 °C. The alloy is intended for use in TVELs of modern nuclear reactors. Product Description popup.authors Baibara Anatoliy A Valerii Valerii G. Zorin Volodymyr О Kytranov Dmytro S Kondrashev Oleksandr I Luhovsʹkyy Yuri F Maksymchuk Ihor M Malka Oleksandr M Medalovych Nina P Nyshchenetsʹ Vitaliy M Romanko Petro M Sliusareva Valentyna S Spiridonov Serhiy A Tkachenko Volodymyr G Frizelʹ Viktor V Khryplyvyy Anatoliy O popup.nrat_date 2023-02-02 Close