Relative Density of SLM-Produced Aluminum Alloy Parts: Interpretation of Results

Abstract

Micrographic image analysis, tomography and the Archimedes method are commonly used to analyze the porosity of Selective Laser Melting (SLM)-produced parts and then to estimate the relative density. This article deals with the limitation of the relative density results to conclude on the quality of a part manufactured by additive manufacturing and focuses on the interpretation of the relative density result. To achieve this aim, two experimental methods are used: the image analysis method, which provides local information on the distribution of porosity, and the Archimedes method, which provides access to global information. To investigate this, two different grades of aluminum alloy, AlSi7Mg0.6 and AM205, were used in this study. The study concludes that an analysis of the metallographic images to calculate the relative density of the part depends on the areas chosen for the analysis. In addition, the results show that the Archimedes method has limitations, particularly related to the choice of reference materials for calculating relative density. It can be observed, for example, that, depending on the experimental conditions, the calculation can lead to relative densities higher than 100%, which is inconsistent. This article shows that it is essential that a result of relative density obtained from Archimedes measurements be supplemented by an indication of the reference density used.

Nanoscale Synthesis of Li1.3Al0.3Ti1.7(PO4)3 Solid-State Lithium Ion Battery Electrolyte: A Structural and Ionic Conductivity Study

“…Higher relative density leads to higher ionic conductivity density. The density is measured in IPA as a medium and calculated by the following eq ρ normals normala normalm normalp normall normale = ρ f × m normala normali normalr false( m normala normali normalr − m f false) where m air mass of the sample in air, m f mass of the sample in IPA, and ρ f density of IPA (0.786 g/mL).…”

“…Higher relative density leads to higher ionic conductivity density. The density is measured in IPA as a medium and calculated by the following eq where m air mass of the sample in air, m f mass of the sample in IPA, and ρ f density of IPA (0.786 g/mL).…”

Laser Powder Bed Fusion of ODS 14YWT from Gas Atomization Reaction Synthesis Precursor Powders

“…The imageJ particle analysis toolpak was then used to calculate the area fraction of the observed porosity. 45,46 Vickers hardness measurements of the as-fabricated solids were made using a LECO M400 microhardness tester with a diamond indenter (500 g-force, 10-s dwell). General microstructure, EDS, and electron backscatter diffraction (EBSD) characterization were accomplished using a ThermoFisher Helios 5 Hydra CX and plasma Focused Ion Beam (pFIB).…”

Shock Hugoniot of Forged and Additively Manufactured 304L Stainless Steel

“…These values are shown in Table 2. It is important to note that it has been documented in the literature that accurately measuring the density of AM samples, especially with porosity, can be complicated especially using standard immersion techniques [29][30][31]. In presence of porosity, liquid can fill the "pores" and cause a larger error in the density measurements [29].…”