• Marteleur, Matthieu
• Rest, Camille Van De
• Simar, Aude
• Gheysen, Julie

Abstract

The main drawback of laser powder bed fusion (L-PBF), commonly called selective laser melting (SLM) is the high porosity which may lead to an early failure of the parts. To minimize it, the L-PBF parameters need to be optimized focusing on the laser power, scanning speed and hatching space. Many studies have optimized the L-PBF parameters by analyzing density of samples with different L-PBF parameters, analyzing single scan tracks (SST), etc. However, no standard guideline exists. In this study, an efficient and cost-effective optimization methodology is developed and validated on AlSi12. This innovative methodology brings together SST and macroscopic properties analysis with design of experiments (DOE). It requires three batches of: 1. SST: for the analysis of the geometrical features of the melt pool 2. Cubes: for density analysis 3. Tensile specimens: for static mechanical properties analysis. This work shows that nine SST are sufficient to identify a process window that is 85% similar to the one obtained from a full factorial design with 105 SST. This process window based only on 9 SST already reliably leads to high densities (>99.3%). After refinement of the process window based on the cube analysis, the optimized L-PBF parameters lead to better mechanical properties in comparison to the state-of-the-art properties reported in the literature for L-PBF AlSi12. In conclusion, a methodology using only nine SST, 18 cubes and 12 tensile tests has been validated on AlSi12. It is further envisioned to optimize the L-PBF parameters of any existing alloy leading potentially towards better mechanical properties than that currently in the literature.

Topics

• density
• impedance spectroscopy
• experiment
• melt
• selective laser melting
• porosity