Effects of high-energy electro-pulsing treatment on microstructure, mechanical properties and corrosion behavior of Ti–6Al–4V alloy

• Rapid recrystallization of Ti alloy occurred under electro-pulsing treatment (EPT).
• Heterogeneous effect was found in agreement with selective effect of EPT.
• Ductility of the materials was greatly improved to 32.5% by EPT.
• Anti-corrosion performance was improved by forming moderate oxidation layer.
• EPT oxidation kinetics of Ti alloy strips was put forward.

The effect of electro-pulsing treatment (EPT) on the microstructure, mechanical properties and corrosion behavior of cold-rolled Ti–6Al–4V alloy strips was investigated in this paper. It was found that the elongation to failure of materials obtains a noticeable enhancement with increased EPT processing time while slightly sacrificing strength. Fine recrystallized grains and the relative highest elongation to failure (32.5%) appear in the 11 second-EPT samples. Grain coarsening and decreased ductility were brought in with longer EPT duration time. Fracture surface analysis shows that transition from intergranular brittle facture to transgranular dimple fracture takes place with an increase in processing time of EPT. Meanwhile, corrosion behavior of titanium alloys is greatly improved with increased EPT processing time, which is presented by polarization test and surface observation with the beneficial effect of forming a protective anatase-TiO2 film on the surface of alloys. The rapid recrystallization behavior and oxide formation of the titanium alloy strip under EPTs are attributed to the enhancement of nucleation rate, atomic diffusion and oxygen migration resulting from the coupling of the thermal and athermal effects.