Enhanced superplasticity for (α<hsp></hsp>+<hsp></hsp>β)-hot rolled Ti–6Al–4V–0.1B alloy by means of dynamic globularization: Fid-Bau Portal

Enhanced superplasticity for (α+β)-hot rolled Ti–6Al–4V–0.1B alloy by means of dynamic globularization

Roy, Shibayan / Suwas, Satyam

Highlights • Higher elongation for Ti–6Al–4V–0.1B alloy compared to base Ti–6Al–4V alloy. • Faster dynamic globularization ensuring narrow distribution of equiaxed α grains. • Higher amount of α/β interface and increased level of boundary sliding. • Balance between dynamic globularization and coarsening dictating final grain size. • Localized cavitation due to strain accumulation around TiB not leading to crack.

Abstract Thermo-mechanically processed Ti–6Al–4V alloy, with (0.1wt.%) and without boron addition, has been subjected to tensile test under superplastic deformation conditions (Temperature, T =850°C and initial strain rate, $\dot{ε} = 3 \times 10^{- 4}$ s⁻¹). The boron added alloy exhibited higher elongation (∼430%) in comparison to the base alloy without boron (∼365%). Superior ductility of the boron added alloy has been attributed to an enhanced α/β interfacial boundary sliding. This was caused by riotous dynamic globularization leading to the abundant presence of equiaxed primary α grains with refined sizes and narrow distribution in the deforming microstructure. Cavities do occur around TiB particles during deformation; the cavities are, however, extremely localized and do not cause macroscopic cracking.