Microstructure and texture evolution in titanium subjected to friction roll surface processing and subsequent annealing
(1. State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology,
College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, China;
2. Department of Mechanical and Intelligent Engineering, Graduate School of Engineering,
Utsunomiya University, Utsunomiya 321-8585, Japan;
3. Department of Materials Science, Graduate School of Engineering,
Osaka Prefecture University, Sakai 599-8531, Japan)
College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, China;
2. Department of Mechanical and Intelligent Engineering, Graduate School of Engineering,
Utsunomiya University, Utsunomiya 321-8585, Japan;
3. Department of Materials Science, Graduate School of Engineering,
Osaka Prefecture University, Sakai 599-8531, Japan)
Abstract: Commercial purity and high purity titanium sheets were initially strained by a new technique, named as friction roll surface processing (FRSP). Severe strain was imposed into the surface layer and strain gradient was formed through the thickness of the sheet. The microstructure and texture in as-strained state were investigated by optical microscopy and X-ray diffraction technique. On the surface of the sheets, ultra-fine grains were found to have a sharp texture with a preferred orientation strongly related to the FRSP direction. The evolution of microstructure and crystallographic texture of FRSPed samples during recrystallization were also studied by electron back-scattered diffraction (EBSD) technique after being annealed at selected temperatures and time. The results indicated that the preferred orientations resulting from FRSP and annealing in the surface layer were formed during rolling and its recrystallization textures were reduced by FRSP. In addition, the texture evolved stably without change in main components during the annealing.
Key words: titanium; friction roll surface processing; severe plastic deformation; preferred orientation; recrystallization; texture evolution; ultra-fine grains