Formation phenomena of cladding layers were observed with high speed video camera to analyze the cladding layer formation process. The influence of the overlap rate and laser beam profile were also investigated on formation process of cladding layer. High speed video revealed that the bottom of the laser beam having low power intensity melted only powder material without melting the substrate and gathered powder to be a globular shape. This caused the lack of powder material, melting of the substrate and mixing substrate to cladding layer by the following laser irradiation. The gathering of powder material was suppressed by using a copper slit to shape laser beam profile. It was found that the laser beam profile strongly affected the laser
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