Encyclopedie de la recherche sur l'aluminium au Quebec - Edition 2014 | Page 76

74 Effect of Laser Scanning Strategy on TRANSFORMATION ET APPLICATIONS // TRANSFORMATION AND APPLICATIONS Morphology and Microstructure during Selective Laser Melting (SLM)
 EFFET DE LA STRATÉGIE DE BALAYAGE LASER SUR LA MORPHOLOGIE ET Effet de la strategié de balayage laser LA MICROSTRUCTURE LORS DE LA FUSION SÉLECTIVE AU LASER sur la morphologie et la microstructure lors de la fusion EFFECT OF LASER SCANNING STRATEGY ON MORPHOLOGY AND sélective au laser. MICROSTRUCTURE DURING SELECTIVE LASER MELTING (SLM) R. Trespalacios1, M. Brochu1 1 Department of Mining and Materials Engineering, McGill University. Introduction The fabrication of additive manufactured (AM) aluminum alloy parts has recently attracted increasing interest from the aerospace industry due to the possibility of producing complex net-shape components that are lighter than parts made using established processes, while at the same time eliminating non-recurring tooling costs and increasing production flexibility. However, the additive manufacturing of aluminium alloys represents a major challenge due to the residual stresses, solidification cracking and porosity associated with the process. A laser scanning strategy for powder based Selective Laser Melting (SLM) of aluminum alloys can be designed to reduce overall residual stress, cracking and porosity by influencing the solidification and cooling rate during processing. Methodology Common Laser Scanning Strategies SLM process Laser Scan Strategy Design Temperature from Single Pulse Modelling of powder bed heat extraction. Optimal Path Generation. 3D model slicing and ‘island’ generation. Materials Selective Laser Melting. Results AA 2024 AA 2080 Optimized Printing Pattern AA 2080 SEM image AA 2024 Powder Characteristics AA 2080 Powder Characteristics Mean Diameter 50.94 µm Mean Diameter D10 32.10 µm D10 8.15 µm D50 Rodrigo Trespalacios Mathieu Brochu Département de génie des mines et des matériaux, Université McGill AA 2024 SEM image 57.41 µm D50 16.27 µm D90 75.23 µm D90 29.50 µm Apparent Density 1.42 g/cm Apparent Density 1.22 g/cm Copper Content (wt%) 3.8 - 4.9 % Copper Content (wt%) 3.3 - 4.1 % 17.50 µm Conclusions - Optical microscope and SEM image analysis of the control samples processed using conventional scanning patterns show unacceptable levels of porosity and cracking within the specimen. - Results from the new scanning pattern remain to be studied. Future Work SLM is a complicated process, it’s quality dependent on a large number of parameters. Although preliminary results show good promise, further investigation on the effect of new scanning strategies on micro-segregation, microstructure and residual stresses must be conducted. References [1] Lore Thijs et Al. A study of the microstructural evolution during selective laser melting of Ti–6Al–4V, Acta Materialia, March 2010. Journée des étudiants – REGAL The fabrication of additive manufactured aluminum alloy parts has recently La fabrication additive des pièces en alliage d'aluminium a récemment attiré l'intérêt de l'industrie aérospatiale par la possibilité de produire des pièces complexes à finition immédiate. En \