Aluminum becoming titanium

NUST MISIS scientists have proposed a technology that can double the strength of 3D printing composites from aluminum powder and change the characteristics of these products to the quality of titanium alloys: the strength of titanium is about six times that of aluminum, but the titanium density is 1.7 times higher.

Modifiers developed for 3D printing can be used in products intended for the aerospace industry.

The developed modifying precursors, based on nitrides and aluminum oxides and obtained by combustion, became the basis of the new composite. The results of the research were published in a highly rated scientific journal. Sustainable materials and technologies.

Two decades ago, molding was considered the only cost-effective way to make bulk products. Today, 3D printers for metal are an excellent competitor of metallurgical methods. 3D printers have the ability to replace traditional metallurgical production methods in the future. The use of additive technologies with 3D printing creates a whole range of benefits, ranging from the creation of more difficult forms and designs to the lower cost of technology and its theoretical advantage.

Today, several technologies are used for the printing of metals, the main ones being Selective Laser Fusion (SLM) and Selective Laser Sintering (SLS). Both involve the gradual superposition of ink, layer by layer, of metal powder to form a given volume. SLS or SLM are additive manufacturing technologies based on layer-by-layer sintering of powdered materials with the aid of a powerful laser beam (up to 500 W).

Titanium is the optimal metal for manufacturing products for the aerospace industry. However, it can not be used in 3D printing, because of the risk of fire and explosion of powders. Aluminum is an alternative because it is lightweight (density 2700 kg / m³) and moldable, having a modulus of elasticity of ~ 70 MPa. This is one of the industry's main requirements for a metal to be suitable for 3D printing; however, aluminum alone is not strong enough nor solid: the tensile strength, even for Duralumin alloy, is 500 MPa and its Brinell HB hardness is 20 kgf / mm².

The research team led by Professor Alexander Gromov of the NUST MISIS Department for Nonferrous Metals and Gold has proposed the solution to enhance 3D printing to aluminum.

"We have developed a technology to reinforce 3D printed aluminum matrix composites and obtained innovative precursor modifiers by burning aluminum powders.The combustion products – nitrides and aluminum oxides – are specially prepared for the sintering of branched surfaces with transition Nanocoats formed between the particles, it is the special properties and the structure of the surface that allow the particles to be firmly fixed to the aluminum matrix and, therefore, [doubles] the strength of the composites obtained, "said Alexander Gromov, head of the research group.

Currently, the team of developers is testing the prototypes with the help of a new technology.

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More information:
G.N. Ambaryan et al, Advanced manufacturing process of α-Al2O3 of very high purity, Sustainable materials and technologies (2018). DOI: 10.1016 / j.susmat.2018.e00065