Is your invaluable smartphone in glass and metal?
Metallic glasses can become a super-durable coating for gadgets
A unique method of processing bulk metal glasses was proposed by NUST MISIS material scientists. They managed to find production conditions that significantly improve the quality of these promising materials. They can be used as coatings for expensive smartphones, tablets, as well as the manufacture of biocompatible implants. Research results published in the journal Journal of Alloys and Compounds.
MetaMetallic glasses (amorphous metals) – materials that, in contrast to “classical” materials with a crystal lattice, have no regularity in the arrangement of atoms far apart from each other. Because of this, they are distinguished by high strength, elasticity, corrosion resistance and other properties, due to which they are in demand in instrument making, mechanical engineering, medicine and magnetic electrical engineering.
However, there is always a fly in the ointment. One of the obstacles to the widespread use of these materials is their high fragility. The study authors believe that a new method of processing metal glasses will help solve this problem. The method was tested on an amorphous alloy of the system zirconium-copper-iron-aluminum (Zr-Cu-Fe-Al).
“The use of annealing before and after rolling was“ prohibited ”by the canons of the science of metallic glasses, since in the vast majority of cases this leads to their embrittlement. The choice of the alloy composition and alloying system helped us to get around this problem: annealing at about 100 degrees below the glass transition temperature made it possible, instead of embrittlement, to achieve plasticization of bulk samples and hardening of tape “- explained the research supervisor of the study, Doctor of Technical Sciences, Professor of NUST MISIS, Dmitry Luzgin.
According to the authors of the study, the characteristics of the obtained material are influenced by the method of decomposition of the alloy matrix – strip or bulk. Depending on this, different results are achieved.
“For bulk samples, by dividing a homogeneous amorphous phase into two, an increase in tensile ductility of up to 1.5% at room temperature has been achieved. For strip samples, an increase in hardness by 25% was achieved, which is provided by the precipitation of glassy nanoparticles with a size of about 7 nm of the secondary amorphous phase with retention of plasticity for bending and compression. This is an unexpected and very significant result ”, – Anna Igrevskaya, co-author of the method, a researcher at the Department of Metallurgy of Non-Ferrous Metals, NUST MISIS, said.
Alloy Zr-Cu-Fe-Al systems cannot be used as the main structural material due to its high cost, – the authors of the development explain, – however, they are confident that the proposed technology can be applied to other amorphous alloys, in particular, titanium (cheaper).
The new method will simplify the process of imparting the necessary properties to metal glasses, thereby expanding the scope of their use. In the future, the research team intends to apply the new technology for the production of titanium and other volumetric metallic glasses of improved quality.