Tailoring microstructure and mechanical properties of CP-Ti through combined treatment of pressure and pulsed electric current

Abstract

In this work, a new processing technology of pressure plus pulsed electric current treatment (PPEC) was proposed to treat CP-Ti to simultaneously enhance its strength and ductility. Specifically, the CP-Ti was subjected to 50 MPa pressure and pulsed electric current (PEC) with variable intensities (1400A, 1600A, and 1900A) using a spark plasma sintering system. Afterwards, the microstructure evolution, texture change, and mechanical properties were characterized by XRD, EBSD, and tensile tests. The increased grain size and noticeable microstructure change occurred with increasing PEC intensity. Additionally, applying 50 MPa pressure leads to the formation of finer α lamellae colonies and higher content of high-angle grain boundaries, which act as barriers for dislocation motion after yielding, resulting in enhanced strain hardening rate and consequently improved mechanical properties. The processed CP-Ti exhibits a yield strength of 350 MPa, an ultimate strength of 702 MPa, and a significant plastic strain of 39.1%, superior to those of CP-Ti processed by severe plastic deformation and pure PEC treatment. The results provide a new strategy to develop Ti materials for demanding structural applications.