Effect of prestrain on the microstructure and corrosion resistance of 840 nickel-based alloy

The microstructure, grain size, dislocation density, and crystal texture of a material vary owing to prestraining due to external forces. These changes directly affect the corrosion behavior of the material, thereby affecting the structural integrity and service life of the equipment. Thus, this study investigated the impact of 0 %–25 % prestrain on the microstructure and corrosion properties of Incoloy 840, a nickel-based alloy steel. This research explored the relationship between the grain size, low-angle grain boundaries, geometrically necessary dislocation density, dislocation distribution, and corrosion properties. When the prestrain was less than 20 %, the material had fewer defects, and the corrosion performance was influenced by the grain size and low-angle grain boundaries. The highest corrosion resistance was observed with a prestrain of 20 %. Conversely, higher prestrain levels increased the number of defects and dislocation density, thereby rupturing the passivation film and reducing the corrosion resistance of the material.