Aluminum-niobium alloys produced by laser surface alloying: Their structure and properties Available to Purchase

Aluminum-niobium alloys present considerable strength and hardness, being promising materials for structural applications and as coatings. This paper reports results of a study on the structure and properties of Al-Nb coatings produced by laser alloying. Sound, defect-free coatings are produced, provided that proper surface treatment techniques are used. The composition of the surface layers was Al-37.6 (±3) wt.% Nb and their microstructure is formed of dendrites of Al₃Nb and a small volume fraction of interdendritic α-Al. The Vickers microhardness of the surface alloys is high, owing to the large amount and fineness of Al₃Nb intermetallic compound. It varies from 480 to 650 HV, depending on the volume fraction and dendrite arm spacing of Al₃Nb dendrites. Despite the brittleness of Al₃Nb the coatings did not show any tendency to crack, probably because of the presence of the thin interdendritic film of ductile α-Al, which allows for a better accommodation of the generated stresses, and stops the propagation of microcracks that may develop in the intermetallic compound particles.