Solidification behaviour during laser microcladding of Al–Si alloys

•Clad tracks with the submillimeter width were produced by Al–Si alloy microcladding.•Structure formation mechanism during laser microcladding was investigated.•Microhardness of the single Al–Si clad tracks is about 270–300 HV0.05.•Clad walls less than 300 μm wide with aspect ratio of about 7.5 were manufactured.•Clad walls demonstrate a smooth surface with the roughness value RZ = 0.63 μm.

The aim of the present work is to investigate features of low-density materials' structure formation during laser microcladding. Clad tracks with the submillimeter width were successfully produced by laser microcladding of the low-density Al–Si hypereutectic alloys. Microstructures produced with various process parameters and with various chemical compositions of the cladding material were investigated. Structure formation mechanism of Al–Si alloys during laser microcladding was discussed. The influence of laser microcladding on the solidification process and on the final solidification microstructure was studied. The influence of structure formation mechanism on the mechanical properties of the solidified material was investigated. The clad walls less than 300 μm wide with aspect ratio of the long and short sides about 7.5 were manufactured. Structure changes that occurred during the placement of many layers on top of each other were discussed. Mechanical properties and surface roughness of the clad walls as well were investigated. Possibility of using the laser microcladding technique to produce a volume in the submillimeter range was demonstrated.