Densification Behavior and Microstructures of the Al–10%Si–0.35Mg Alloy Fabricated by Selective Laser Melting: from Experimental Observation to Machine Learning

Abstract

This work examined the behaviors of densification and microstructural formation of the Al10 mass%Si0.35 mass%Mg alloy fabricated by Selective Laser Melting (SLM) method on the basis of experimental work and machine learning. Additionally, the effect of scanning repeated twice in each layer (double scanning) in the SLM process was also investigated. The SLM-ed Al10 mass%Si0.35 mass%Mg alloy exhibited the columnar grained microstructure with a (¡-AlSi) eutectic cell structure. Refined microstructures were produced at an increasing scanning speed with a decreasing the energy density (J/mm 3 ). Relative density tended to increase with an increasing of energy density for scan pitch conditions of 0.1 mm and 0.05 mm. And a scattering was obviously exhibited at a higher relative density more than 95%. The analysis based on machine learning revealed that a scanning pitch of 0.2 mm was just a condition to achieve a high relative density. Except for the condition at a scanning pitch of 0.2 mm, a scan speed was the most important factor in affecting the relative density. Thus, a machine learning approach enabled to identify the important processing factor for affecting the behavior quantitatively. Additionally, compared to a conventional single scanning process, it was found in this work that the double scanning resulted in a higher relative density with keeping the fine microstructural formation.

Microstructural Variations in Laser Powder Bed Fused Al–15%Fe Alloy at Intermediate Temperatures

“…Consequently, L-PBF-processed Al alloy products exhibit significantly refined microstructures [5][6][7][8], which lead to higher strengths than those of the Al alloys fabricated using conventional casting processes [9][10][11][12]. Al-Si-based alloys are known to be suitable for the L-PBF process [13][14][15]; however, L-PBF-processed Al-Si-based alloys exhibit reduced strength at temperatures higher than 200 • C [16]. The potential application of L-PBF-manufactured Al alloys in radial impellers operating at intermediate temperatures above 200 • C (inside the vehicle turbochargers) has encouraged the development of new Al alloys with superior strength at both ambient and intermediate temperatures.…”