Physical properties and microstructures of Fe3Al matrix laser amorphous–nanocrystals reinforced coating

An amorphous–nanocrystals reinforced coating was fabricated on the important aeronautical material TA2 alloy by laser cladding of Fe3Al–B4C–TiN mixed powders. The TiB2 nanocrystals were produced through the in situ metallurgical reactions, which blocked the motion of dislocation, and also refined the microstructure of the coating. The productions of amorphous/nanocrystalline phases were due to the action of the sufficiently rapid heating and cooling of the laser cladding technique, and a number of elements with short atomic radius. Ti and Fe components have negative enthalpies of mixing, so usually, the free energy of amorphous alloy was lower than that of these two crystalline components mixture, leading to the formation of amorphous alloy.

► Laser cladding of Fe3Al-B4C-TiN powders can form amorphous-nanocrystals reinforced coating.
► The TiB2 nanocrystals were produced through the in situ metallurgical reactions.
► A portion of amorphous material began to crystallize when molten pool had completed solidification process.
► Ti and Fe components have negative enthalpies of mixing, favoring the formation of amorphous alloy.