What’s up in the materials lab?
Last week, the upcoming five and maybe for the rest of my career, I’ll be located in the materials laboratory, my “home department”. During my studies in materials engineering, I often got questions about what my work would be like once finished. As I typically answered: I’ll be cutting up metals, grinding metals or looking at metals, I feel it’s time to explain the work in more details, for anyone interested. So, what are we doing?
My story may be a bit focused on metallography, since it’s what I’m doing right now, but I’ll try to include something brief about the rest of the activities at the department. The materials lab (informally the name of the department) mostly receives components and samples in need of examination from the producing units. The chemistry lab gets samples of process fluids, such as coolants from mechanical processing or etching baths, while the metallography lab deals with whole components (replica testing), segments of them (destructive testing) or process samples. Some of the metallographic work is shared with a smaller lab connected to the preparation of thermal coatings, where components get their hard, soft or corrosion resistant surface layers. Sometimes, samples from mechanical testing that have gone through experiments to obtain material data, arrives at the lab.
In the metallography lab materials from different production processes are evaluated to make sure everything went as expected. What are we looking for? Metallic materials consist of crystals (!), usually many but may in the aerospace industry be a single one, which greatly influence the properties of the product. Such crystals can be seen on galvanized lamp posts, as angular shapes of different shades. In most cases these are microscopically small (not the lamp posts) and you’ll need instruments to see them, for instance a microscope. The size and chemical composition of the crystals can be altered through alloying elements (ingredients in the metal), heat treatments and processing. If you can assess the microstructure, you can control if the production had been proper. Often sample preparation (as cutting, grinding and etching) is required to develop the right features for the examination.
Defects, like cracks and pores, may also be studied, since they determine how the material will perform or not. In the latter scenario the cause of component failure can be investigated (fractography). Surface layers, desired from thermal coating as well as unwanted, created in heat treatments, are also checked.
As you see, there’s a wide variation to the jobs at the lab and a lot of different analysis techniques available at the department. Whether it’s hacksawing away on a metal sheet or a microscopy assessment, I really enjoy my job and I’m looking forward to learning much more in the field! Thank you, dear and diligent reader! I’ll keep it shorter in posts to come!
Have a great day!