Characterization of Flow Stress for Commercially Pure Titanium Subjected to Electrically Assisted Deformation

Uniaxial tension tests were conducted on thin commercially pure (CP) titanium sheets subjected to electrically assisted deformation using a new experimental setup to decouple thermal-mechanical and possible electroplastic behavior. The observed absence of stress reductions for specimens air-cooled to near room temperature motivated the need to reevaluate the role of temperature on modeling the plastic behavior of metals subjected to electrically assisted deformation, an item that is often overlooked when invoking electroplasticity theory. As a result, two empirical constitutive models, a modified-Hollomon and the Johnson-Cook models of plastic flow stress, were used to predict the magnitude of stress reductions caused by the application of constant dc current and the associated Joule heating temperature increase during electrically assisted tension experiments. Results show that the thermal-mechanical coupled models can effectively predict the mechanical behavior of commercially pure titanium in electrically assisted tension and compression experiments.