Semi-quantitative study of amorphous structures in laser cladding of ZL111 aluminum alloy

This paper deals with amorphous structures in the laser cladding. A kind of Ni-Cr-Al alloy was sprayed on the substrate, which was ZL111 alloy, to be the coating material. The coating was clad by a 5 kW transverse flow CO2 laser. The observation of SEM and TEM revealed that in the laser cladding there were amorphous structures which appeared two different morphologies: one was space curved flake-like, which existed in the white web-like structures; the other was fir leaf-like, which existed in the grain-like structures. Differential thermal analysis (DTA) was used to semi-quantitatively determine the content of the amorphous structures. A curve relation was obtained between the content of amorphous structures and the dimensionless laser cladding parameter C. The changes of the amorphous structures after annealing were also shown.