Characterisation of laser-cladded 410 stainless steel for in situ repair of turbine blade

Abstract

Laser cladding was employed to apply a pure nickel powder coating onto 410 stainless steel turbine blade material, utilising a 50 W pulsed diode fibre laser system. Various process parameters were explored, including average laser power (20 W, 30 W, 40 W) and scanning speeds (SSs) (0.5 mm/s, 1 mm/s, 1.5 mm/s). The pulse width and frequency were fixed to 110 ns and 50 kHz, respectively. Successful deposition of nickel powder was accomplished at an average power of 40 W at various SSs. The microstructure, phase components, clad geometry, tensile properties, and microhardness of cladded specimens were examined. The experimental results show that the cladding layer has a metallurgical bonding with the substrate, having a visual interface with no cracks or defects. The clad layer's height peaked at 1 mm/s (175.889 μm), while the maximum clad depth occurred at 0.5 mm/s (367.797 μm). Predominant intermetallic phases observed included FeNi3, Cr1.36Fe0.52, along with fine carbides (M3C, M7C3, M23C6 where M – Fe, Ni). Enhanced mechanical properties were observed in the cladded samples compared to the substrate. At 1 mm/s SS, the clad zone exhibited the highest microhardness (221.4 HV), tensile strength (482.03 MPa), and Young's modulus (17.97 GPa).