Microstructure and Texture Evolution of Repetitive Upsetting-Extruded (RUEed) Mg-Gd-Y-Zn-Zr Alloy after Hot Compression

In order to determine the deformation temperature of next pass, the hot compression tests were performed by Gleeble-3800 at different temperature form 380 to 420 °C. The microstructure and texture evolution of repetitive upsetting-extruded (RUEed) Mg-Gd-Y-Zn-Zr alloy during hot compression were studied by electron backscattering diffraction (EBSD) analysis. The results showed that the dynamic recrystallization (DRX) occured during the hot compression processing from the strain-stress flow curves. When the temperature increased to 420 °C, the average grain size reduced to 6.64 μm, and the volume fraction of DRXed grains increased to 81.5%. All the compressed alloys exhibited a typical compression texture, the maximum texture intensity of {0001} plane gradually decreased with increasing temperature. When the compression temperature was up to 420°C, the the maximum texture intensity of {0001} plane was 3.207 due to the effect of DRXed grains. Finally, 420°C is chosen as the next deformation of next pass because of the more precipitation and DRXed grains.

FORMATION FEATURES OF ADIABATIC SHEAR BANDS DURING HOT COMPRESSION OF VTI-4 ALLOY AND SUBSEQUENT ANNEALING

Textural and macrostructural changes in the intermetallic titanium alloy VTI-4 based on the orthorhombic phase (Ti2AlNb) during hot high-rate compression and subsequent recrystallization annealing where studied. The main attention is paid to the formation features of localized deformation bands (LDB) in the central zone of the compressed sample, which are one of the signs of unstable and nonuniform deformation. It is shown that recrystallization annealing after hot compression does not eliminate the LDB and the compression texture. Reasons for this behavior of the material are studied applying the analysis of the solid solution state.