The scientists at Togliatti State University (TSU) have developed a unique method to receive magnesium and magnesium alloy based foam materials. The Federal Service for Intellectual Property has issued a patent on the invention.
A lightweight and high strength together with excellent damping properties are the main advantages of metal foams still preserving all values and worthiness of the starting materials. The TSU scientists hold 14 patents on invention relating to porosity based composite materials.
The experimental works carried out by them earlier made it possible to obtain porous aluminum, copper, nickel and even steel. Their latest development is a method for producing porous materials from magnesium and its alloys. This metal has the lowest density and high damping properties compared to other structural metals, and this makes it very attractive for industry.
“Magnesium is difficult to work with metallurgically, it has a low ignition temperature, but it is a very promising material. Our method allows obtaining a light porous metal, the density of which is lower than the density of water. This foam material has high specific strength, it better dampens the impact energy during a collision, mechanical vibrations, for example, vibration” – explains Alexander Kovtunov, professor of the Department of Welding, Pressure Processing of Materials and Related Processes at the Institute of Mechanical Engineering (INMASH), TSU.
The essence of the method is that the heated magnesium alloy is poured into a mould with granules of sodium chloride. After solidification, the casting is leached by placing it in a 5-35% aqueous solution of acetic acid. The granules dissolve, and the magnesium casting forms a porous structure.
“The presence of acetic acid allows to get a clean surface of the finished material without traces of interaction with sodium chloride from the granules, it also reduces the rate of magnesium corrosion in the resulting salt solution and ensures the dissolution of corrosion products in the solvent” – Alexander Kovtunov says.
The advantage of the technology is its simplicity, the ability to obtain both simple and complex shapes of castings, low cost, as well as sufficiently high productivity. The method proposed by the TSU scientists makes it possible to obtain porous magnesium with a controlled pore size and both homogeneous and heterogeneous porosity. In October 2020, the authors of the invention filed an application with the Federal Service for Intellectual Property and in June 2021 received a patent for the development.
Magnesium foam materials can be used in the aerospace and automotive industries, where it is of great importance to reduce the weight of the structure while maintaining its strength. As Alexander Kovtunov noted, manufacturers of aviation components have already expressed interest in the new technology.
*Damping — raising a disipation of an energy in order to increasingly reduce oscillation within a system.