AN OVERVIEW OF LASER CLADDING: FATIGUE EFFECT MECHANISMS AND PREDICTIONS

Laser cladding is an advanced surface modification technology that utilizes a high-energy laser beam to form a molten pool on the metal substrate and solidifies rapidly to form a bonding layer between the cladding material and the substrate. Compared with other surface modification technologies such as electroplating, thermal spraying, EDM and laser cutting, laser cladding has the advantages of small thermal deformation of the substrate, narrow heat-affected zone, and fast cooling of the molten pool, which makes it more and more widely used. When laser cladding is used to repair railroad axles, thin-walled blades, and other workpieces, fatigue resistance is one of the key performance metrics to be evaluated after cladding. This paper summarizes the factors that significantly affect the fatigue resistance of workpieces during laser cladding. The mechanisms underlying the fatigue resistance of the workpiece are analyzed from the perspectives of material properties, initial defects, and residual stresses, and the effects of other factors on fatigue-related mechanical properties are analyzed. Additionally, traditional and state-of-the-art fatigue life prediction methods are summarized, and the development of advanced algorithmic techniques for fatigue life prediction in the laser cladding process is discussed.