Effect of process parameters on the microstructure and mechanical properties of AA2024 fabricated using selective laser melting

Pekok, M. A. ORCID: https://orcid.org/0000-0003-1888-5057, Setchi, R. ORCID: https://orcid.org/0000-0002-7207-6544 and Ryan, M. ORCID: https://orcid.org/0000-0002-8104-0121 2021. Effect of process parameters on the microstructure and mechanical properties of AA2024 fabricated using selective laser melting. International Journal of Advanced Manufacturing Technology 112 , pp. 175-192. 10.1007/s00170-020-06346-y

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Abstract

Selective laser melting (SLM) offers significant benefits, including geometric freedom and rapid production, when compared with traditional manufacturing techniques. However, the materials available for SLM production remain limited, restricting the industrial adoption of the technology. The mechanical properties and microstructure of many aluminium alloys have not been fully explored, as their manufacturability using SLM is extremely challenging. This study investigates the effect of laser power, hatch spacing and scanning speed on the mechanical and microstructural properties of as-fabricated aluminium 2024 alloy (AA2024) manufactured using SLM. The results reveal that almost crack-free structures with high relative density (99.9%) and Archimedes density (99.7%) have been achieved. It is shown that when using low energy density (ED) levels, large cracks and porosities are a major problem, owing to incomplete fusion; however, small gas pores are prevalent at high-energy densities due to the dissolved gas particles in the melt pool. An inversely proportional relationship between ED and microhardness has also been observed. Lower ED decreases the melt pool size and temperature gradients but increases the cooling rate, creating a fine-grained microstructure, which restricts dislocation movement, therefore increasing the microhardness. The highest microhardness (116 HV0.2), which was obtained from one of the lowest EDs used (100 J/mm3), is 45% higher than as-cast AA2024-0, but 17% lower than wrought AA2024-T6 alloy.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Additional Information:	This article is licensed under a Creative Commons Attribution 4.0 International License
Publisher:	Springer Verlag (Germany)
ISSN:	0268-3768
Date of First Compliant Deposit:	18 November 2020
Date of Acceptance:	2 November 2020
Last Modified:	05 Jan 2024 08:49
URI:	https://orca.cardiff.ac.uk/id/eprint/136111

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