Microstructure of titanium deformed by warm extrusion with forward- backward rotating die

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Sztwiertnia, K.^1 ; Morawiec, A.^1 ; Bieda, M.^1 ; Kawalko, J.^1

Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Krakow, Poland^1

关键词: Coincidence site lattices;    Electron back scatter diffraction;    Grain fragmentation;    Heterogeneous microstructure;    Low angle boundaries;    Misorientation angle;    Misorientations;    Twin boundaries;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012012/pdf
DOI  :  10.1088/1757-899X/63/1/012012

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The principal KoBo device is a press with a forward-backward rotating die, enabling the extrusion of ingots under conditions of constant destabilization of their substructure. Polycrystalline grade 2 titanium was subjected to warm KoBo type extrusion. Microstructure of the material was investigated by means of Electron Backscatter Diffraction (EBSD) in the scanning electron microscope. It clearly shows deformation-induced grain fragmentation. The EBSD maps reveal heterogeneous microstructure built of ribbons curled about the extrusion direction (ED) and some equiaxed or cigar-like grains. Sizes of grains vary in the range 70-1500 nm for the minor axis and 350-20000 nm for the major axis. The material has a relatively sharp nearly axial texture with theaxis perpendicular to ED. In misorientation angle distribution, besides the peak at low angle boundaries, there are three other peaks at about: 29.7deg, 89.7deg and 93.2deg. They do not correspond to any twin boundaries or low Σ coincidence site lattice misorientations.