Quantitative analysis: How annealing temperature influences recrystallization texture and grain shape in tantalum

The recrystallization behavior of tantalum was investigated under two different annealing regimes, i.e. long-time annealing at low temperatures (LALT) and short-time annealing at high temperatures (SAHT), aiming to elucidate how annealing schedule arouses not only different texture evolution but grain shape as well. The texture and grain morphologies at each recrystallization stage were revealed by Electron Back-Scatter Diffraction (EBSD) technique. LALT was observed to enhance the {100} texture (< 100 >//ND (normal direction)) while simultaneously suppressing the {111} texture (< 111 >//ND); whereas a reverse trend of texture evolution was observed under SAHT. In terms of grain shape, different from the near-equiaxed grains introduced by LALT, SAHT resulted in lots of elongated grains with random orientations (i.e. orientations except for {111}< uvw > and {100}< uvw >). The formation mechanism of elongated grains was established. It is anticipated that results in this study would provide guidelines for microstructural optimization of Ta sputtering targets.