Aerosol induced processing efficiency improvement for drilling micro holes with high aspect ratios in nickel-based alloys

High aspect ratio holes in nickel-based alloys have significant applications in the film cooling of aircraft turbine engines. The high inlet temperature (>2200°C) of the next generation turbine engine imposes stringent requirements on the cooling efficiency of its hot components such that the commercial macro-hole cooling with cooling efficiency ≤60% cannot meet the requirements. Micro cooling holes with diameter of ∼0.1 mm are proposed to generate up to 90% cooling efficiency. However, current processing techniques face challenges of inefficient debris removal and debris redeposition on the inner walls, making it difficult and inefficient to fabricate high aspect ratio holes with diameters ≤0.1 mm. In this work, an aerosol assisted laser spinning method is proposed to fabricate free tapered or reverse tapered holes with diameters ≤ 0.1 mm and aspect ratios ≥20 in nickel-based alloys. The aerosol modulates the laser intensity distribution and the hole’s perforation time is reduced by 35.6%. This study provides a cost-effective drilling efficiency improvement method for fabricating high aspect ratio micro-holes in opaque materials with broad applicability, particularly in processing micro cooling holes in turbine engines.