Research On The Evolution Of Microstructure And Texture Of High-purity Tantalum Through Different Rolling Methods And Annealing Process

High purity tantalum sputtering targets are used widely in electronic information products industry. The quality of high purity tantalum sputtering targets is strongly affected by the homogeneity of microstructure and orientation distribution. In order to control the homogeneity of microstructure and texture of high purity tantalum targets more effectively, clock rolling with rotating 135°after each pass was used. The evolution of microstructure and texture during different rolling methods (unidirectional rolling and clock rolling) and different annealing process was investigated with optical microscopy (OM), X-ray diffraction, SEM and EBSD. The main conclusion found are as follows:①After the clock rolled Ta annealed at 1050℃for 60min, the recrystallized grain size decresed with the increasing of reduction ratio.②The two main texture components of unidirectional rolled Ta were {111}<112> and {111}<110>, The {001}<110> and {112}<110> texture components increased with the increasing of reduction ratio. The 87% unidirectional rolled Ta sheet showed typical bcc rolling texures, {112}<110> is the most strong rolling texture, following by {111}<112>, {111}<110> and {001}<110> is the last strong texture in rolled bcc texture.③No {112}<110> texture component was found in unidirectional rolled Ta. {111}<112> and {111}<110> textures which nearγ-fiber reached max in all rolled texture at 87% reduction during clock rolling. The clock rolled Ta with same last pass rolling direction but different reduction ratio showed very similar texture.④Abnormal grain growth was found in the sheet annealed at 1300℃for 60min, but after annealed at 1400℃for 60min, the recrystallized grain size of the annealed sheet decresed, and secondary recrystallization generated.⑤The clock rolled Ta sheets were annealed at different temperature for 60min, {001}<100> texture decreased with the increasing of annealing temperature. The texture of Ta annealed at 900℃for 60 min revealed a high intensity ofγ-fibre, after annealed at 1000℃for 60 min the intensity of theγ-fibre was reduced. Then, with the increasing of anneal temperature, the recrystallized texture of {111}<110> and {111}<112> enhanced. {001}<100> and{001}<110> textures were vanished after annealed at 1400℃for 60min.