Correlation of strain path and crystallographic texture with electrochemical behavior of Ti-15V-3Cr-3Sn-3Al alloy

Abstract

Effect of strain path and crystallographic texture on electrochemical properties of cold-rolled Ti-15V-3Cr-3Sn-3Al (all elements in weight%, designated as Ti-15333) alloy has been studied in the present investigation. The as-received specimens with and without solution annealing (SA) were subjected to different strain paths to reduction ratio (RR) of 40% and 80%. The microstructure showed the presence of shear bands (SBs) in all the deformed specimens and its fraction increased with increase in the RR. With the increase in deformation, α- and γ- fibers were observed in all the specimens. Electrochemical potentio-dynamic tests followed by open circuit voltage were used to investigate the passivity and pitting corrosion in 3.5% NaCl solution for both the undeformed (as-received, SA) and deformed Ti-15333 alloy specimens. A complementary assessment was employed to analyze the influence of work-hardening on passivity and pitting corrosion behaviors of Ti-15333 alloy systematically, combined with additional investigation of electrochemical impedance spectroscopy (EIS). High corrosion resistance was observed for the SA specimen than non-SA (as-received) specimen. Increase in the RR from 40% to 80% increased the corrosion rate for all the strain paths, except multi-step cross-rolled (MSCR). Corrosion resistance of the 80% deformed specimens were dependent on both the evolved microstructure (SBs, grain fragmentation) as well as crystallographic texture. Multi-step cross rolling resulted in the formation of a strong Rotated Cube ({100}<110>) texture, which was expected to be the reason for its enhanced corrosion resistance.