Metals, plastic, ceramics, and composites are used by engineers every day. We all know common properties like; metals are strong but heavy, plastics are lighter and ceramics can shatter. But mechanical and material engineers have been developing new engineering materials to solve problems with amazing ingenuity. New designs are born from biomimicry, experimentation and sometimes plain luck.
1) Microlattice Metals
Our first look at unique engineering materials is a super light but rigid metal foam called a Microlattice metal. This super porous metal is notable for its impressive strength to weight ratio. It is one of the lightest structured materials ever created, in fact, it is even described as being around 100x lighter than styrofoam. Microlattice metals are structurally similar to bone; rigid on the outside, but mostly air on the inside.
Popular applications for this material include shock absorbers, battery electrodes, lightweight vehicles and any situation where relatively light but extremely strong materials are required.
Aerogels are a classification of unique engineering materials incredibly similar to the Microlattice in their structure. Aerogels, sometimes described as liquid smoke, are made from a silica gel which has had all of its liquid removed. While both are remarkably lightweight, Aerogels are unique for their thermal conductivity, or almost complete lack of thermal conductivity. These properties could make Aerogels useful for insulating crafts with minimal weight requirements like spaceships. Additionally, the silica structure of Aerogels can be combined with other materials to create AeryClays. By mixing polymer clay into the mixture this can drastically change the mechanical properties or even add new exciting possibilities for the materials.
Aerogels have an array of different forms and are used in such diverse applications as insulation to skylights, chemical absorbents for cleaning-up spills, thickening agents in paints and cosmetics, passive thermal protection for divers and the creation of so-called supercapacitors.
3) Self Assembling Engineering Materials
Imagine your chair being able to fold itself together or a flat hat popping up into shape. Researchers at MIT have been working to develop smart materials which can, almost automatically, fold or refold themselves into a predefined configuration. The goal is to create a ‘robotic material’ which can be used to fix and assemble itself as needed. Fully assembled pieces can take up a lot of space but these materials can lay flat until needed and then reform themselves when exposed to a certain electric current.
Smart materials have been created which change their form when voltage is passed through them, others react to temperature change, changing magnetic fields, changing acidity as well as optical variations. We have only just scratched the surface in relation to the potential use of smart materials.
4) Spider Silk (artificial)
For many years Spider Silk has been known for its incredible tensile strength and elasticity – it has a wide variety of uses in the animal kingdom from trapping prey, using long webs to move between trees or gliding. In many ways we are just now beginning to learn about the unique characteristics of this intriguing material which many of us encounter on a daily basis.
As an engineering material spider silk could be used to create ultra lightweight and resilient clothing, high strength ropes, surgical bandages and thread, or even artificial tendons for biomedical applications. This really is a case of when engineering meets nature!
What other unique engineering materials have you found interesting or useful? Let us know some of your favorites below!