Researchers have used carbon nanofibres derived from oil waste to increase the hardness of 3D printed aluminium products by 50 per cent.
The developed nanocarbon additive, obtained from the products of processing associated petroleum gas, could be used to improve the quality of 3D printed aerospace composites when added to aluminium powder.
The work has been described in Composites Communications.
Today, the main field of application for aluminium 3D printing is the creation of parts for the aerospace industry.
The presence of even the slightest defects in printed structures is critical to the safety of the technology being created. According to the researchers, from The National University of Science and Technology in Moscow, the main risk of such defects is the high porosity of the material, caused – among other reasons – by the qualities of the original aluminium powder.
To ensure a uniform and dense microstructure of printed products, the researchers proposed adding carbon nanofibres to the aluminium powder. The use of this modifying additive makes it possible to ensure a low porosity of the material, and an increase in its hardness by 1.5 times.
‘Changing the chemical and phase composition of the powder for printing by introducing additional components into the main matrix allows improving its properties,’ said professor Alexander Gromov, head of the laboratory where the work took place. ‘In particular, carbon nanofibres have high thermal conductivity, which helps to minimise temperature gradients between printed layers during product synthesis, at the stage of selective laser melting. Thanks to this, the microstructure of the material can be almost completely eliminated from inhomogeneities.’
The technology for the synthesis of nanocarbon additives developed by the research team includes methods of chemical deposition, ultrasonic treatment, and IR heat treatment.
The used carbon nanofibres must be a by-product of associated petroleum gas processing. During its catalytic decomposition, carbon accumulates in the form of nanofibres on dispersed metal particles of the catalyst. Usually, at present, associated gases are simply burned in the fields, which harms the environment. Therefore, the application of the new method also has a serious environmental significance.
In the future, the research team plans to determine the optimal conditions for selective laser melting of new composite powders, as well as to develop a technology for the post-processing and industrial use of synthesised products.
This work was carried out jointly with specialists from the Boreskov Institute of Catalysis SB RAS.