Figure 1a shows the X-ray diffraction patterns of Fe-based amorphous alloy powders. It can be observed from the figure that there is an obvious broad halo peak around the diffraction angle of 45◦ and 75◦ (2θ), and there are several weak peaks of crystalline phases. Therefore, the powders are mainly composed of amorphous an phase, together with a small amount of crystal phases.
Figure 1b shows the X-ray diffraction patterns of the multi-track laser cladding. A broad halo peak representing the amorphous phase can be observed around the diffraction angle of 45◦ (2θ). There were also several peaks of crystalline phases on the curve. The peaks of crystalline phases were identified as carbides (Fe, Cr)23C6, Cr7C3, and solid solution Fe63Mo37.
The Pseudo-Voigt function was used to fit the peaks of amorphous phases and crystalline phases, respectively, and the area of the peaks of amorphous phases and crystalline phases were calculated. The volume fraction of the amorphous phase was calculated using the following formula:
By calculation, the volume fraction of the amorphous phase in the cladding layer obtained under the selected process parameters is about 52.8%, compared with 85.7% in the powder
Figure 1. XRD patterns of the powders and the multi-track laser claddings, showing the (a) powders and (b) the cladding layers.
The cross-section morphology of the single-track laser cladding is shown in Figure 2. The surface of the cladding layer is smooth. The maximum thickness of the cladding layer is about 580 µm. Three distinct areas can be observed: the upper cladding layer, the heat affected zone in the middle, and the substrate at the bottom.
Figure2. The low-magnification scanning electron micrograph of the single-track laser cladding.
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