Laser Cladding with Preplaced Powder: Analysis of Thermal Cycling and Dilution Effects

Abstract

A theoretical model has been developed which analyses thermal cycling during the laser cladding process. The preplaced powder cladding method investigated involves scanning a defocused or rastered laser beam over a powder bed which is subsequently melted and welds to the underlying substrate. Previous practical work has shown that minimal dilution effects can be observed over a very large range of processing parameters. Theoretical modelling of the movement of the molten front has shown that after initial clad melt-substrate contact the melt recedes from the substrate and will only cross the cladding/substrate interface again under extreme conditions of input energy and laser-material interaction time.