Transmission electron microscopy characterization of laser-clad iron-based alloy on Al-Si alloy

Microstructure characterization is important for controlling the quality of laser cladding. In the present work, a detailed microstructure characterization by transmission electron microscopy was carried out on the iron-based alloy laser-clad on Al-Si alloy and an unambiguous identification of phases in the coating was accomplished. It was found that there is austenite, Cr7C3 and Cr23C6 in the clad region; α-Al, NiAl3, Fe2Al5 and FeAl2 in the interface region; and α-Al and silicon in the heat-affected region. A brief discussion was given for their existence based on both kinetic and thermodynamic principles.