Five Key Metallurgy Concepts

In this video, I'll explain about five key metallurgy concepts. They're important for understanding how to engineer metals - to produce stock metals such as rod, bar, and sheet, to design and fabricate components, and to figure out the root cause of component failures and production quality problems.
The first concept is crystallinity. Metals are crystalline, which means that the atoms are arranged in a periodic manner. Now the specific arrangement of atoms can can differ from metal to metal, but the fact remains that the metal that the atoms are arranged in the periodic manner. And this is important because this affects the behaviors of metals compared to other other materials.
The second concept is metallurgical phases. Phases are physically distinct materials within metals. A phase can be either a mixture or a compound. Phases have different properties. So when more than one phase is present in a metal, the metal is basically a composite material and the properties of the material depend on the properties of the different phases that are present. Understanding the phases that can be present in an alloy and what can be done to influence the phases present is important for understanding how to use metal composition and metal processing to modify the phases present in order to modify the properties of the metal.
The third concept is phase transformations. We can heat treat a metal by heating it or cooling it to cause changes in the phases present. The changes in the phases present is called a phase transformation. By controlling the composition and the heat treatment of a metal, we can control the phases that are present as well as their shape and their size and in other other factors related to the phases. All of these influence the properties of a metal.
The fourth concept is diffusion. Diffusion means the motion of atoms through a metal. Diffusion enables changes to occur to metal microstructure during heat treatment, resulting in changes metal properties. Understanding diffusion is important for understanding the changes that occur during heat treatment.
And the final basic metallurgy concept that's important to understand is dislocations. There are dislocations are present in all metals. There are about 10 million dislocations per square centimeter in as cast metals. Dislocations are important because they influence the mechanical properties of metals. By understanding how move through a metal and the things that affect dislocation motion, we can engineer metals (composition and microstucture) to modify metal strength and other mechanical properties.