Papers by Author: V.V. Cheverikin

Abstract: In this article, perspective using of the laser deposition method for manufacture details from the titanium alloy VT20 is considered. Dependence on a structure of the fractional composition is shown. Study of the structure and properties of parts, which were produced by DLD technology using different modes and under different conditions.

Abstract: The evolution of surface, grains and dislocation structures during superplastic deformation was studied in Al–6.8%Mg–0.6%Mn–0.25%Cr alloy by SEM, EBSD, TEM techniques. The effective activation energy of superplastic deformation was calculated. Contribution of grain boundary sliding was defined during superplastic deformation. Low value of grain boundary sliding, significant dynamic grain growth in stress direction, high dislocations activity and permanent continuous formation of sub-grain boundaries during superplastic deformation were found.

Abstract: The formation of eutectics in Al–Zn–Mg–Ni and Al–Zn–Mg–Si systems is studied by means of metallography, DSC, EPMA, X-ray spectroscopy and thermodynamical calculations. Polythermal sections of the corresponding phase diagrams are constructed. The concentrations and temperatures of binary eutectic reactions L → (Al) + Al3Ni and L → (Al) + Mg2Si in quaternary alloys are determined. Nonequilibrium solidification in Al–7% Zn–3% Mg-based alloys ceases at approximately 480 °C. The alloys close by composition to binary eutectics have considerably improved casting properties as compared to the base Al–7% Zn–3% Mg composition. In particular, hot tearing susceptibility is much less in alloys with Al3Ni or Mg2Si. These results are corroborated by measurements of thermal contraction during solidification. The alloys containing binary eutectics exhibit much lower temperatures of contraction onset and less thermal strain is accumulated in the solidification range. Fine eutectic morphology enables fragmentation and spheroidization of intermetallic particles during annealing. The presence of Al3Ni and Mg2Si particles does not decrease the precipitation hardening effect associated with precipitation of the T′ (AlMgZn) phase. Improved casting properties and good mechanical properties of castings allow the application of Al–Zn–Mg alloys with binary eutectics formed by Al3Ni or Mg2Si as foundry alloys.