Trans‐Conductive Melt Pool Scaling and its Implications for Parameter Transfer in Laser Powder Bed Fusion for Metals with High Thermal Diffusivity

For the development of alloys for laser powder bed fusion, it is desirable to enable a free choice of laser scan speed while avoiding porosity formation. This is due to the role of scan speed and melt pool size/shape in determining microstructure formation from solidification and associated mechanical properties. It is found that melt pool depth predicts the optimum in porosity formation, independent of the scan speed. To transfer this optimum melt pool depth to different scan speeds, the normalized enthalpy β and the normalized energy density (), an extension of the volume energy density, are examined for four binary aluminum–nickel alloys. Without modifications, these energy input parameters cannot be applied over a wide range of laser scan speeds for materials with high thermal diffusivity. The Peclet number is used to distinguish between high and low scan speeds relative to the material's thermal diffusivity. By calculating the absorptivity from melt pool width and examining the trans‐conductive (Peclet number around 1) melt pool scaling, it is found that the native formulations of β and need to be multiplied by the Peclet number to be applicable for low laser scan speeds.