43 Hydrogen Effects on Plastic Deformation of AISI 316LN Single Crystals Available to Purchase

Single crystals of 18Cr12Ni2Mo austenitic stainless steel with loading axis orientation of [001] and [$1¯$11] were tensile tested with the on-line optical observation of the slip pattern development in order to study the hydrogen effects on the dislocation slip at the early stages of multiple slip. Hydrogen was introduced electrochemically at the controlled potential for charging time which allows a hydride-free distribution of hydrogen across the tensile specimens. It is found that hydrogen increases the yield stress and plastic flow stress of the studied steel and promotes multiple slip. AFM observations of the fine structure of the slip offsets reveal that in the hydrogen-free specimen their average height is about 95 nm, while in the presence of hydrogen the average slip step height decreases to about 30 nm. In the presence of hydrogen the fine slip offsets form bands with total slip step height markedly higher than that in the steel without hydrogen.