Laser metal deposition influence on the mechanical properties of steels and stainless steel composites: A review

Reported works on laser alloyed steels have been reviewed. The premature failure of engineering steels when employed in harsh working conditions is due to low hardness, poor tribological behaviour and corrosion resistance. The engineering solutions to minimize or eliminate such initiated failure lie in tailoring the surface composition and microstructure through laser surface alloying. The reviews affirm that cracks, pores and micro-segregation associated with LSA greatly affect the quality and damage the properties of the alloyed zone. The powder materials for laser alloying process must be selected based on application requirements and that the achievement of a strong fusion bond over the entire interface between the substrate and the alloyed layer is an essential aspect of laser alloying. Therefore, good wettability between the coating materials and the substrate is also required. The review established a relationship between the important process parameters (Laser power, scanning sped, powder feed rate) on the hardness, microstructure, wear and corrosion resistance of alloyed steels. Finally, to achieve a very high material efficiency, excellent laser alloyed coatings, as well as the desired properties, the right combination of the process parameters is very necessary, and this can be achieved through optimization of the process parameters.