Effect of heat treatment and laser surface remelting on AlSi10Mg alloy fabricated by selective laser melting
The selective laser melting (SLM) of aluminium alloys is of interest to researchers because of these alloys’ potential applications in the aerospace and automotive domains. Post-processing is generally required in order to enhance the mechanical properties of devices that involve moving parts, where surface mechanical properties are significant factors. This paper describes a preliminary study that was conducted to investigate the effect of post-processing on the microstructure and mechanical properties of SLM fabricated AlSi10Mg alloy, with an emphasis on the laser surface remelting (LSR) process. The experimental results demonstrate that the heat treatment degraded tensile strength while improving ductility by achieving grain growth and residual stress release. The yield strength obtained in the experiment was reduced from 200 to 100 MPa, whereas the elongation increased from 6 to 22%. The LSR process was found to contribute to an improvement in surface finish. The surface roughness indicator Ra was determined to be 0.93 μm in the LSR post-processed sample, compared to a fairly high value of 19.3 μm in the as-fabricated samples. The LSR process also enhanced the microhardness by refining the microstructure; the Si eutectic dendritic structure that formed was found to be finer than that of the as-fabricated samples. Compared to the as-fabricated samples, the LSR process contributed to a 19.5% increase in microhardness. The findings suggest that the microstructure and mechanical properties of SLM-fabricated AlSi10Mg parts could be tailored by suitable post-processing such as heat treatment and LSR. The significance of this research is its proposal of a novel technique to enhance surface hardness using LSR, which is a significant step towards the combination of SLM and LSR processes to manufacture customised aluminium components for the automotive and aerospace sectors.
KeywordsSelective laser melting Aluminium alloys Heat treatment Laser surface remelting Microstructure
The authors would like to thank Mr. Haiyang Fan from KU Leuven, Belgium, for the SEM operations and valuable discussions.
- 15.Maskery I, Aboulkhair NT, Corfield MR, Tuck C, Clare AT, Leach RK, Wildman RD, Ashcroft IA, Hague RJM (2016) Quantification and characterisation of porosity in selectively laser melted Al-Si10-Mg using X-ray computed tomography. Mater Charact 111:193–204. https://doi.org/10.1016/j.matchar.2015.12.001 CrossRefGoogle Scholar
- 17.Del Re F, Contaldi V, Astarita A et al (2018) Statistical approach for assessing the effect of powder reuse on the final quality of AlSi10Mg parts produced by laser powder bed fusion additive manufacturing. Int J Adv Manuf Technol 97:2231–2240. https://doi.org/10.1007/s00170-018-2090-y CrossRefGoogle Scholar
- 19.Li W, Li S, Liu J, Zhang A, Zhou Y, Wei Q, Yan C, Shi Y (2016) Effect of heat treatment on AlSi10Mg alloy fabricated by selective laser melting: microstructure evolution, mechanical properties and fracture mechanism. Mater Sci Eng A 663:116–125. https://doi.org/10.1016/j.msea.2016.03.088 CrossRefGoogle Scholar
- 24.Standard test methods for tension testing of metallic materials. https://compass.astm.org/Standards/HISTORICAL/E8E8M-13A.htm. Accessed 15 Sep 2018
- 27.Li XP, Wang XJ, Saunders M, Suvorova A, Zhang LC, Liu YJ, Fang MH, Huang ZH, Sercombe TB (2015) A selective laser melting and solution heat treatment refined Al-12Si alloy with a controllable ultrafine eutectic microstructure and 25% tensile ductility. Acta Mater 95:74–82. https://doi.org/10.1016/j.actamat.2015.05.017 CrossRefGoogle Scholar
- 28.Prashanth KG, Scudino S, Klauss HJ, Surreddi KB, Löber L, Wang Z, Chaubey AK, Kühn U, Eckert J (2014) Microstructure and mechanical properties of Al-12Si produced by selective laser melting: effect of heat treatment. Mater Sci Eng A 590:153–160. https://doi.org/10.1016/j.msea.2013.10.023 CrossRefGoogle Scholar
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