Influence of spindle speeds on the microstructure,formability,and corrosion behavior of grade 2 commercially pure Titanium sheets processed by multi point incremental forming (MPIF)

The grade 2 commercially pure titanium (CP-Ti) sheets were incrementally deformed using the multipoint incremental forming (MPIF) process, where sheets of thickness up to 1 mm were deformed with the aid of a six-spherical ball-ended tool. Frustum cups were made at spindle speeds of 200, 250, and 300 rpm. In MPIF, shape changes in sheet metals can be achieved without the use of a punch and die, even for ultra-thin materials. Therefore, this process is recommended for fabricating parts in the automotive, aerospace, and biomedical industries. This research focused on studying formability through electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), and X-ray diffraction (XRD) analysis, to investigate the phase analysis, grain orientation, and dislocation density. Potentio Dynamic Polarization (PDP) tests were conducted to investigate the corrosion behavior of both the BM and deformed samples. Morphological studies of the corrosion pattern were conducted using a scanning electron microscope (SEM) at various spindle speeds following the MPIF process. The influence of spindle speed on the forming limits of Grade 2 CP-Ti was investigated. Maximum plastic deformation (plasticity), higher dislocation density, and enhanced corrosion resistance were observed at a higher speed (300 rpm), due to the strengthening of the basal texture and weakening of the prismatic texture components. The Forming Limit Strain (FLS) was drawn for different spindle speeds (200, 250, and 300 rpm). The FLS was correlated with microstructural, mechanical, and corrosion properties at different spindle speeds.