Influence of the thermal-fluid behavior on the microstructure evolution during the process of selective laser melting of Ti6Al4V

Investigating the relationship between mechanical properties and residual stress in the laser cladding process of Inconel 625 superalloy

“…Regarding magnitude, the local residual stresses can contribute to a high percentage of the yield stress of the material (up to75%). Generally, additivly manufacturing parts are entangled with the significant residual stresses [ 1 , 2 ], which is influenced by process parameters including laser power, scanning velocity, overlap percentage and characteristics of the substrate and powder. By optimizing these parameters and features, the residual stress can be reduced to a great extent, but still, some amounts of residual stress remain in the workpiece [ [16] , [17] , [18] , 46 , 47 ].…”

“…Appropriate heat treatment can release stresses. However, the deformation created during the cladding process may lead to incompatibility with the desired geometry and even deteriorate the uniformity of the product or generally, the quality of the cladding [ [1] , [2] , [3] ].…”

“…Generally, laser cladding processes have high heating and cooling speeds, especially at the solid-melt interface, with values around 10 8 K/s. The lack of required time for the formation and growth of grains, leads to the creation of a fine-grained structure [ 2 , 3 ].…”

“…In the laser cladding process, due to the input heat, a high-temperature gradient is created. During the cooling, these gradients, coupled with different material properties, lead to different thermal contractions, and consequently, high residual stresses can be found in the cladding layers [ [1] , [2] , [3] ]. When the tensile residual stresses in the deposited layers are high, the formation of cracks are almost guaranteed.…”