Research on microstructures and properties of Inconel 625 coatings obtained by laser cladding with wire

Laser cladding has been widely applied in surface modification and repairing. In this study, single bead and multiple beads Inconel 625 coatings were fabricated on the surface of 316L stainless steel by laser cladding. This investigation was conducted using an optical microscopy, scanning electron microscope (SEM), X-ray diffraction (XRD) and other methodologies. A three-dimensional (3D) finite element (FE) model was applied to predict the temperature evolution in the laser cladding process. The results indicated that the defect-free Inconel 625 coating presented an obvious microstructure transformation while the bonding interface can be divided into three different areas. An unmixed area was observed near the bonding interface with precipitated ferrite of different formations. A decrease of the hardness (H) and reduced elastic modulus (Er) profile was detected in this area. Cladded area and bonding area exhibited superior tensile properties at both room temperature and high temperature than substrate. The corrosion performance of coating area was also close to bonding area and superior to substrate in different solutions, indicating an excellent protecting effect of Inconel 625 coating.