The microstructure, mechanical property and corrosion behavior of magnesium alloy WE43 (MgYNdZr alloy) in the environment simulating biological fluid were investigated. Samples of ultrafine-grained magnesium alloy with high mechanical properties were obtained by methods of severe plastic deformation. Programmed plastic deformation was realized by two methods: extrusion alternating with upsetting at gradually lowering the temperature and equal-channel angular pressing.

The purpose of this study was to obtain pure nanostructured titanium by drawing at cryogenic temperatures and to investigate its structural and mechanical properties. Titanium rods were obtained by severe plastic deformation under the scheme of upsetting-extrusion-drawing. Upsetting and extrusion were performed at 800 K, obtained rod was initially drawn at 300 K to diameter of 3.7 mm (degree of true strain e = 3.2). Further deformation of the finish drawing was performed at 77 K (liquid nitrogen) and at 300 K.Keywords: titanium / medical implants / plastic deformation / nanostructure / mechanical properties / Das Ziel dieser Arbeit war die Herstellung von reinem nanostrukturiertem Titan durch die Tiefzieh-Verformung bei kryogenen Temperaturen und die Untersuchung seiner strukturellen und mechanischen Eigenschaften. Titanproben (Stäbe) wurden durch die starke plastische Verformung beim Pressen-Extrusions-Tiefziehen hergestellt. Das Pressen und die Extrusion wurden bei 800 K durchgeführt, der erhaltene Stab wurde zuerst bei 300 K zu einem Durchmesser von 3,7 mm gezogen (wahre Dehnung e = 3,2%). Eine weitere endgültige Verformung wurde durch Tiefziehen bei 77 K (flüssiger Stickstoff) und bei 300 K durchgeführt.

This is a study of the effect of quasihydrostatic extrusion at liquid nitrogen and room temperatures on the evolution of the structure and mechanical properties of high-purity titanium produced by severe plastic deformation in a swaging-extrusion-drawing regime and with subsequent annealing at temperatures of 350–550 °C. It is shown that a combination of severe plastic deformation and cryogenic quasihydrostatic extrusion makes it possible to create high-purity nanocrystalline titanium with high strength and plasticity.

The results on investigations of mechanical properties of high-purity titanium with grains ranging from tens of nanometers up to a few micrometers subjected to uniaxial tension, compression and microindenting are presented. Different structural states in high-purity titanium were formed by severe plastic deformation according to the scheme «upsetting – extrusion – drawing» in combination with annealing at temperatures of 250–550° C and quasi-hydrostatic extrusion at room and liquid nitrogen temperatures. The values of yield strengths and microhardness for samples of high-purity titanium with grains of different sizes are determined. It was shown that the combination of severe plastic deformation with cryogenic quasi-hydrostatic extrusion allowed to create high-purity nanocrystalline titanium with high mechanical properties. The obtained experimental data were analyzed for the implementation of the Hall-Petch relation and discrepancy between the values of yield strengths in tension and compression (strength differential or S-D effect). Satisfactory fulfillment of the Hall-Petch relation for high-purity titanium in the whole range of the studied grain size values was shown and a noticeable difference in the yield values for compression and tension was found. The values of the coefficients in the Hall-Petch equation for deformation by tension, compression and microindenting were determined. These coefficients are noticeably lower than the corresponding values for the industrial grades of titanium, i.e. in high-purity titanium, the grain boundaries are weaker barriers for moving dislocations than in the industrial titanium, whose boundaries are enriched with impurities. The features of the acoustic waves emission during compression of samples in various structural states were studied. It was concluded that the deformation of titanium in all the investigated structural states was carried out by dislocation slip.