Mechanism of In Situ Action of a Pulsed Electric Current during Tension of Coarse-Grained Grade 4 Titanium

The mechanism of action of a low-duty-cycle pulsed current during plastic deformation of biomedical coarse-grained grade 4 titanium is discussed. Mechanical tensile tests with temperature monitoring, microhardness measurements, and microstructural analysis by optical microscopy of specimens deformed without current and with current according to schemes differing in the sequence of current switching on/off are performed. One of the specimens is tested without current after preliminary loading with current. The deformation behavior and the mechanical properties of titanium are analyzed using stress–strain curves. The lower the duty cycle of the current, the greater the decrease in the flow stress and the elongation to failure. The strength properties of the material preliminarily deformed with a low-duty-cycle current are shown to recover almost completely upon subsequent current-free tension. This fact, as well as the results of optical microscopy and microhardness determination, indicate an in situ mechanism of the electropulsing action. The investigation results can be used to form titanium at temperatures below the recrystallization onset threshold while preserving the initial structure and mechanical properties