Formation of Submicrocrystalline Structure in Titanium and its Alloy under Severe Plastic Deformation

摘要

The mechanical behavior and structure formation during deformation under high pressure of titanium and Ti64 alloy were studied. It was shown that deformation at low temperature (0.4 T_m) leads to the formation of structure with grain size less than 0.5 μm both in the Ti and Ti64. The contribution of the strengthening processes with decreasing deformation temperature is appreciably increased. The mechanism of titanium structure formation depends on the temperature of deformation. During low temperature deformation (<650 °C) new grains are formed according to the continuous mechanism via formation of subgrains with the following increase in their misorientation whereas at high temperatures the formation of new grains occurs via discontinuous dynamic recrystallization. The microstructure evolution in the Ti64 at studied temperatures is connected with recrystallization of phases according to the continuous mechanism and accompanied by phases spheroidization.