Novel hybrid laser forging and arc additive repairing process for improving component performances

Abstract

A new hybrid laser forging and arc additive repairing process was developed to significantly improve the performance of repaired components, in which a leading gas metal arc was adopted to repair the partially damaged component, and a trailing short-pulse laser directly acted on the high-temperature solidified metal without coating (laser forging). Compared with arc additive repairing with post-treatment, this hybrid process performed the arc repair and laser forging synchronously. The laser forging region can be accurately determined using a multi-physical molten pool simulation. The molten metal flow was also studied, indicating that the high sulfur content introduced by the filler metal transfer had a significant influence on the Marangoni stress distribution and thus changed the molten metal flow patterns. The mechanism for laser forging without coating and its related physical effects were investigated. The laser shock pressure was significantly higher than the Hugonoit elastic limit of the high-temperature solidified metal, causing plastic deformation of the repaired layer. The high strain and severe plastic deformation induced by laser forging caused martensite formation and grain refinement, which improved the mechanical properties and electrochemical corrosion performance of the repaired layer.