Forming and Microstructure Evolution Mechanism of Asymmetric Molten Pool in Laser Cladding

Abstract

This study aimed to investigate the impact of substrate tilt angle and different scanning methods on powder utilization, morphology profile parameters, and microstructure evolution in laser cladding single-track experiments. The results revealed several key findings. Firstly, as the substrate tilt angle increased, the laser spot projected on the tilted substrate transformed from circular to elliptical, and the substrate heat input decreased proportionally with the tilt angle. Secondly, regardless of the scanning method employed, powder utilization decreased with higher substrate tilt angles due to increased powder asymmetry, leading to more collisions and rebounds between the powder particles and the substrate. Moreover, the trends of morphology profile parameters in longitudinal upward and downward scanning methods were similar to the transverse scanning, except for the clad width, which exhibited an opposite trend. Notably, the longitudinal downward scanning method demonstrated superior stability and higher powder utilization. These findings offer valuable insights for optimizing laser cladding processes, with the ultimate goal of enhancing the quality and efficiency of the fabricated components.

Keywords

• laser cladding
• asymmetric molten pool
• power attenuation rate
• powder catchment efficiency
• microstructure