Nanocrystallized Surface Effect on the Tribocorrosion Behavior of AISI 420

Abstract

Nanopeening treatment was applied to the AISI 420 steel to decrease its sensitivity to tribocorrosion damage. The microstructural investigation highlighted that the nanopeening treatment led to high plastic deformation and a nanostructured surface layer with a 110 µm depth. In order to study the combined effect of corrosion and mechanical wear, tribocorrosion tests were performed on non-treated and nanopeened samples in boric acid and lithium hydroxide solutions, considering both continuous and intermittent sliding. It was found that the AISI 420 steel is sensitive to the synergy between mechanical friction and electrochemical corrosion with the dominance of abrasive wear. Adhesive wear was also detected in the wear track. Indeed, the mechanical wear was pronounced under intermittent sliding because of hard wear debris generation from the repassivated layer during rotating time. The nanopeening treatment led to enhanced mechanical performance and corrosion properties. Such improvement could be explained by the high plastic deformation resulting in the nano-structuration of grains and the increasing hardness of AISI 420 steel.

Keywords

• microstructure
• grain size
• hardness
• tribology
• corrosion
• passivation