fault line

What are the elastic limits of the metallic glass? What are the limits of her power? When, and under what pressure, will it react plastically and break anyway? What are the dynamics of fracture development in metallic glass? These are the questions that were at the center of the research conducted by the group of Prof. Itamar Procacia, from the Department of Chemical Physics at the Weizmann Institute of Science.

Glass is a material that lives in two worlds. On the one hand, it looks rigid and solid. On the other hand, its internal molecular structure is not similar to the structure of ordinary solid materials, which are built as an organized lattice crystal.

The atoms and molecules in the glass are placed in disorder, in a mixture, reminiscent of a liquid. But it is a liquid that does not flow. Toothpaste, for example, which is a type of glass, will "flow" in the direction of the opening of the toothpaste tube only if you press the tube.

In recent decades, advanced materials called "metallic glass" have been developed in various parts of the world, which is actually metal organized in a glass structure (non-lattice crystal). These metallic glasses are characterized by great strength, rigidity, durability, and light weight, and in addition, they are relatively easy to magnetize. The production process of metallic glasses is based on melting the metal and cooling it very quickly immediately afterwards, so that the condensed material is not enough to organize into lattice crystals, and its atoms and molecules are more or less "trapped" where they were when the material was liquid. When this is done while mixing different metals - metallic glass is obtained.

When, for example, you drop a ball on the surface of a crystalline lattice material, the ball bounces back, but, due to the defects in the crystalline lattice, it gradually loses kinetic energy, slowing down and reducing its jumps until it comes to a complete stop. On the other hand, metallic glass does not have an ordered crystalline structure, so structural defects cannot exist in it. Therefore, when you repeat this action (throwing a ball on a plate) with a plate of metallic glass, the ball bounces back many times. In other words, the metallic glass almost does not absorb mechanical energy, which gives it great efficiency and charts a "future promotion path" for it in a series of industrial applications, in the fields of computing and engineering.

But what are the limits of the elasticity of the metallic glass? What are the limits of her power? When, and under what pressure, will it react plastically and break anyway? What are the dynamics of fracture development in metallic glass? These are the questions that were at the center of the research conducted by the group of Prof. Itamar Procacia, from the Department of Chemical Physics at the Weizmann Institute of Science. In order to examine the breaking processes, the scientists were required to follow processes that occur very quickly, and are seen differently from different points of view.

The scientists made careful observations of the reactions of metallic glass to various stresses, some of which led to the breaking of the plate. Analyzing the results and their complex weighting allowed them to understand the dynamics of the fracture, and then to develop a way to predict the way in which plates of metallic glass will react to pressures and when, and under what pressure, and under what conditions, these plates may react plastically (and break), and not elastically, i.e. flexibly .