Orientation dependence of stored energy release and microstructure evolution in cold rolled tantalum

• The stored energy of refractory metal Ta was measured with differential scanning calorimetry technique.
• The total stored energy of 87% cold rolled Ta was about 30.6 J/mol, most of which was released during recovery.
• Correlative microstructure evolution during the energy release referred to (i) recovery of all grains, (ii) recrystallization of {111} grains and recovery of {100} grains, and (iii) recrystallization of {100} grains.

The bulk stored energy of cold rolled tantalum (Ta, 87% thickness reduction) was measured by differential scanning calorimetry, and related microstructure evolution during the stored energy release was studied by electron backscatter diffraction method. In addition, transmission electron microscopy was employed to reveal the substructure of the deformed Ta. Results showed that the deformed Ta consisted of {1 1 1} texture (< 1 1 1 > // ND) and {1 0 0} texture (< 1 0 0 > // ND), and its substructure was characterized by dislocation cells or dense dislocation walls. The total stored energy of as-rolled Ta was about 30.6 J/mol, most of which was released by recovery. The release of the stored energy suffered a complicated process and was orientation dependent. Correlative microstructure evolution path during heating referred to (i) recovery of all grains, (ii) primary recrystallization of {111} grains and recovery of {100} grains, and (iii) recrystallization of {100} grains.