In the development of protective alloy layers by laser cladding residual stresses can lead to final cracking of the deposited coating and a certain mechanical deformation of the processed part. These stresses are of thermal nature and result from very high thermal gradients and cooling rates associated to laser heat treatments.
A numerical model based on a thermo-mechanical finite element analysis was developed and is presented which allows to obtain the thermal and stress fields in the laser cladding process. The nature of the stress fields (compressive-tensile) is explained and the effect of the geometrical features of the deposited clad, the thickness of the substrate material, the process scan speed and substrate preheating temperature on the resulting stress fields and mechanical distortions is discussed. The study includes some characteristic features arising in the processing of overlapping laser scans for covering extended areas as well as multilayer single laser scans for 3D direct fabrication. Comparison with experimental results obtained on Co-based laser clad coatings show a good qualitative agreement.