Unveiling the Effect of Ti Micro-Alloying on the Microstructure and Corrosion Resistance of the GH3536 Alloy Processed by Laser Metal Deposition in a Simulated Environment for PEMFCs.

This article addresses the knowledge gap regarding the effect of Ti addition on the microstructure and corrosion behavior of the LMD-processed GH3536 alloy in a simulated solution of proton exchange membrane fuel cells (PEMFCs). The microstructural evolution, corrosion resistance, and passive film characteristics of LMD-processed GH3536 alloy with varying Ti contents were characterized through a variety of techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), X-ray photoelectron spectroscopy (XPS), and a series of electrochemical measurements. The results indicate that the corrosion resistance of the LMD-processed GH3536 alloy significantly improves with increasing Ti content. However, when the Ti content exceeds 0.2 wt.%, the beneficial effect on corrosion resistance is weakened. Two primary mechanisms explain the enhanced corrosion resistance, involving the heterogeneous nucleation of Ti-modified AlO and Ti solute segregation, which promotes grain refinement. In addition, grain refinement can provide more active sites for the formation of compact passive films, thereby improving corrosion resistance of the GH3536 alloy.