Physical properties and microstructures of a BN-NiCoCrAlY laser amorphous-nanocrystal reinforced composite coating

Abstract

An amorphous-nanocrystal reinforced composite coating was fabricated on a TA15 alloy by laser cladding of BN-NiCoCrAlY mixed powders. Experimental results indicated that a portion of the amorphous phases just began to crystallize when the laser molten pool had completed the solidification process. The nucleation and growth of the amorphous phases were retarded by the nanocrystalline phases to a certain extent during the crystallization process. Due to the rapid solidification process of the laser molten pool, a number of the fine precipitates were produced. The production of eutectics, such as Co-Ti and Ti-Si compounds, in such a coating greatly promoted the formation of amorphous phases.

Keywords

• amorphous materials
• coating materials
• laser processing
• nanofabrications
• phase transitions
• thermal analysis