Scientists from Russia’s National University of Science and Technology (NUST MISIS) have developed a new method for increasing the toughness of 3D printed aluminum matrix composites.
This new method of hydrothermal oxidation of aluminum, creates a reinforcement (hardening) oxide film of a certain thickness on the surface of aluminum particles.
In the other words, a ‘package’ is formed on the surface of each spherical particle of pure aluminum.
This helps increase the uniformity of properties and hardness of the obtained 3D printed composites by 40% in comparison with analogs.
The obtained aluminum composite in its characteristics is suitable for use in advanced additive manufacturing and could lead to light and durable cases for aircraft and automotive engineering.
Aluminum matrix composites are a group of advanced materials with a number of unique advantages: they are lightweight, have high strength, low thermal expansion coefficient and excellent wear resistance.
The material owes such properties to its chemical composition and a special method of production – 3D printing using Selective Laser Melting (SLM) technology.
As a result, the composite consists of spherical aluminum particles hardened with ceramic additives or coated with a layer of aluminum oxide.
Alumina is one of the most optimal reinforcement (hardening) additives, and it’s adding into the composition is a typical way to improve the mechanical properties of aluminum composites.
The NUST MISIS team experimentally proved an increase in the strength of the printed composite material due to aluminum oxide by 40 % compared to aluminum without additives.
All said and done, alumina provides a higher heat resistance of the composite powder at elevated temperatures.
It also increases the stability of the powder composition compared with the most common ceramic additives, which makes the material especially useful for aircraft construction.
“The technology is based on the so-called ‘in-situ’ method, meaning the creation of a composite structure within each particle,” explains project head and NUST MISIS professor, Alexander Gromov.
“The initial aluminum powder (with 99.85% purity) has been subjected to partial hydrothermal oxidation in an autoclave for 30 minutes.”
“As a result, an oxide layer with 10 and 20% of Al2O3 content has been formed on the surface of aluminum powder particles.”
Image and content: NUST MISIS