Effect of Chemical Composition Change on Mechanical and Microstructural Properties of Aluminum Alloys Processed by Selective Laser Melting

conference paper

en

Additive manufacturing (AM) has been increasingly used to produce metal components in the last few decades. One of the most popular AM technologies is Selective Laser Melting (SLM). Materials prepared by SLM technology show very good mechanical properties, even though in these materials many defects are present, such as spherical pores, keyhole pores, lack of fusion porosity or cracks. The mentioned defects can be minimized by optimizing the process parameters or changing the chemical composition of the material. Therefore, the objective of this study is to describe changes in the microstructure and mechanical properties depending on the Al alloys chemistry. Three new alloys with different chemical compositions (differs in silica content) were prepared by mechanical mixing of the conventional alloys AlSi12 and AlCu2Mg1.5Ni, and subsequently processed by SLM technology with the same process parameters. Relative density (RD), type of defects, and microstructure were studied in all cases by light microscopy (LM). Mechanical properties were determined by tensile tests performed at room temperature and by hardness tests (HV0.3). Fractographic analysis was performed on fracture surfaces after tensile tests using scanning electron microscopy (SEM). It was found that with an increasing percentage of silica, the RD increases from 95.8 % to 98.8 %. The new alloy with the highest Si content showed the highest tensile test characteristics (UTS = 453 MPa, YS = 243 MPa, and A5.65 = 7.74 %). However, the hardness test did not show a significant difference in the values of individual alloys.

Additive manufacturing (AM) has been increasingly used to produce metal components in the last few decades. One of the most popular AM technologies is Selective Laser Melting (SLM). Materials prepared by SLM technology show very good mechanical properties, even though in these materials many defects are present, such as spherical pores, keyhole pores, lack of fusion porosity or cracks. The mentioned defects can be minimized by optimizing the process parameters or changing the chemical composition of the material. Therefore, the objective of this study is to describe changes in the microstructure and mechanical properties depending on the Al alloys chemistry. Three new alloys with different chemical compositions (differs in silica content) were prepared by mechanical mixing of the conventional alloys AlSi12 and AlCu2Mg1.5Ni, and subsequently processed by SLM technology with the same process parameters. Relative density (RD), type of defects, and microstructure were studied in all cases by light microscopy (LM). Mechanical properties were determined by tensile tests performed at room temperature and by hardness tests (HV0.3). Fractographic analysis was performed on fracture surfaces after tensile tests using scanning electron microscopy (SEM). It was found that with an increasing percentage of silica, the RD increases from 95.8 % to 98.8 %. The new alloy with the highest Si content showed the highest tensile test characteristics (UTS = 453 MPa, YS = 243 MPa, and A5.65 = 7.74 %). However, the hardness test did not show a significant difference in the values of individual alloys.

Selective laser melting, Al alloys, Tensile properties, Fractographic analysis

30.06.2022

TANGER Ltd.

Ostrava

978-80-88365-06-8

31st International Conference on Metallurgy and Materials, METAL 2022

574–579

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