Microstructure and corrosion properties of laser surface processed aluminium alloys: a review

Laser surface treatment techniques, including laser surface melting (LSM) and laser surface alloying (LSA), have been the subject of considerable interest as a means of enhancing the corrosion performance of aluminium and its alloys. Microstructural modification together with the incorporation of non-equilibrium concentrations of alloying elements resulting from relatively rapid rates of cooling compared with conventional surface treatment techniques provide the basis for property enhancement. This paper considers microstructural evolution in a range of laser surface treated aluminium alloys including LSM of Al–Cu, Al–Si, Al–Zn, Al–Fe and Al–transitional element alloy systems; LSA of Al–Ni, Al–Cr and Al–Mo. Where reported, corrosion and other property determination in these systems is discussed. It is shown that surface alloys with unique microstructural and compositional characteristics have been produced by these techniques and that in many cases promising improvements in hardness and critical pitting potential compared with conventional alloys have been reported.