Kutniy K. Effect of severe and cryogenic deformation on the microstructure and properties of titanium and magnesium alloy WE43

Thesis is dedicated to establishment of regularities of evolution the microstructure and physical-mechanical properties of different purity titanium and magnesium alloy WE43 on various types of severe plastic deformation (SPD) in combination with heat treatment and cryogenic deformation, as well as investigation the influence of structural state of magnesium alloy on its dissolution rate in an environment that simulates biological fluid. It was shown that using of different types of SPD (upsetting, extrusion, screw extrusion, drawing) allows to create a different purity titanium with submicrocrystalline structure. Further decrease of grain size in titanium realized through the combination of SPD and cryogenic deformation by quasi-hydrostatic extrusion. As a result high-purity titanium and commercially pure titanium VT1-0 in nanostructured state was obtained and its mechanisms of deformation were studied. By equal channel angular pressing with subsequent heat treatment in magnesium alloy was obtained highly homogeneous ultra-fine-grained microstructure which allowed significantly increase strength and plastic characteristics of the alloy, as well as substantially change the dissolution rate of magnesium alloy in an environment that simulates biological fluid. Proposed combination of different methods of SPD in combination with cryogenic deformation and heat treatment allowed to obtain materials with controlled grain size and improved strength and plastic characteristics. These materials are promising for application in various fields, particularly in medicine, as insoluble (titanium) and soluble (magnesium alloy) implants.