Amorphous Structures in Laser Cladding of ZL111 Aluminum Alloy:Semi-quantitative Study by Differential Thermal Analysis (DTA)

This paper deals with amorphous structures in the laser cladding. ZL111 alloy is the substrate and Ni Cr Al alloy is sprayed on the substrate as the coating material. The coating is clad by a 5 kW transverse flow CO 2 laser. The observation of SEM and TEM reveal that in the laser cladding there are amorphous structures of two different morphologies: one is space curved flake like, and exists in the white web like structures; the other is fir leaf like, and exists in the grain like structures. Differential thermal analysis (DTA) is used to semi quantitatively determine the content of the amorphous structures. A relation is obtained between the content of amorphous structures and the dimensionless laser cladding parameter C. We also show the changes of the amorphous structures after annealing.