The process of laser treatment applied to a metallic surface, which is momentarily surface melted to enable the encapsulation of pre-placed or injected cladding material (metallic or ceramic powder particles). A directed laser beam is scanned and translated over the workpiece (substrate) to melt and solidify the cladding material by using controlled laser power as shown in Fig. A.
FIG. A. Schematic diagram of laser cladding process
The cladding material solidifies rapidly, giving microstructures characterised by fine grain size, fine dendrite arm spacing and a more uniform dispersion of microconstituents such as carbides, nitrides etc. Because of low heat input of this process, distortion of the component is negligible.
Thickness of the coating range from 0.15-50 mm and almost any size of component can be treated. This process is applicable to ferrous or non-ferrous metals and alloys. There has been a lot of interest in recent years in applying such treatments to aluminium and titanium alloys because both of these suffer from the disadvantage of responding poorly to thermochemical diffusion. Laser cladding offers the possibility to develop deeply hardened surfaces up to 1 mm.