Scientists at Russia’s National University of Science and Technology used oil waste to strengthen aluminum alloys used in aluminum powder. The new alloy reduces aluminum’s propensity to residual porosity. “Porosity” refers to gaps between molecules in the alloy that weaken its structure. In other words, the scientists have found a way to strengthen aluminum alloys at a microstructural level. They did so by adding carbon nanotubes to aluminum powders. The scientists reported their results in Composites Communications.
Carbon nanotubes represent a chemical modification to the aluminum alloy’s structure. The nanotubes are composed of carbon that is extracted from oil waste products. These nanotubes are then applied to the microscopic surface of aluminum alloys, thus strengthening the metal by reducing its porosity. The resultant metal is 1.5 times stronger and more rigid than its original composition.
The strengthened products are particularly useful for aerospace and automotive applications. Stronger, unyielding and lightweight materials are prized in these sectors because risk of material failure imports greater danger for the consumer.
Mitigating that risk will require further research. The researchers stress that their process is difficult, which implies that further research will be needed before the technique can be commercialized. Their paper states that: “The process of micron-sized aluminum powders modification by CNTs is rather complex task due to the different particle sizes of micro-Al powders (average particle diameter: 50 μm) and carbon nano-fibers (average particle diameter: 0.05 μm). The innovative solutions are required to achieve the uniform distribution of nano-additive in micron-sized powder.”
The nanotubes are harvested from petroleum gas processing. The chemical separation of gasoline from oil creates nanofibres that adhere to metals added in the refinement process. The waste product is usually burned at refineries, which releases more carbon dioxide into the atmosphere. The new process helps recover some of these waste products before they are transformed into carbon dioxide.
This development is nevertheless welcome because it helps use more oil by-products. Waste would, under this method, be transformed into a resource for additive manufacturing, which makes oil extraction more efficient. This innovation could significantly increase AM’s purchase in the industrial sector while offering a stronger product to manufacturers.