In Awe of Atoms: Lego Blocks of the World around Us

Abstract:

We all know that the stuff around us in made up from atoms. In this talk, I will explain some of important consequences about the physics of the world around us that arise from this simple concept. Many of our useful materials have the atoms arranged in periodic arrangement or as crystals, but the properties of a material often depend, not so much on these periodic atomic arrays, but on the larger scale mis-arrangements of these blocks. These arrangements are called the microstructure of a material as they often exists on a micron length scale and can be seen in a good microscope.

Microstructures are central to the physical and mechanical properties of most materials. Not only failure rates, but many other important properties including strength, susceptibility to corrosion and magnetic and electrical properties, depend crucially on this morphology. Many of the advanced materials, often denoted as “space age” materials, get their properties from tailoring their microstructure by careful and sophisticated processing techniques. Furthermore, it is an important fundamental problem in physics to understand both how such microstructures arise and how to characterize them. Disordered and non-equilibrium systems span the range of materials including binary alloys (Ni3Al used for jet turbines), directionally solidifying crystals (snowflakes) and soft materials (plastic and rubber).

In this lecture I will explain how the dynamics of microstructure describes and controls the properties of materials and how x-ray sources, called synchrotrons, produce x-rays which can be used to study these processes. To understand this lecture, all one needs is a curosity about the world around us.