Some evolving notes on Materials :)

Overview of Different Materials

Riveting vs. Welding Steel

while welding is cheaper in terms of time and labor for steel…
large distance fractures can propagate throughout welded steel and can cause catastrophic failure
- in particular, discontinuities in steel were introduced by inexperienced welders in WW2 (see Liberty ship catastrophic failure)
fractures in riveted metal cannot propagate large distances as they stop at the edge of the sheet of metal
welding is faster (used during WW2 cargo ship mass construction)
riveting is slower but less catastrophic failure change in metal
BUT! Failure is important in processes and materials. Because of the faster iteration introduced by welding…
- these observed failures were useful, since fast iteration happened, welded steel was improved by trial and error in a sense, worked towards removing impurities and adding steel reinforcements

solid materials are grouped into three main categories, scheme based off their atomic structure
- ceramics
- metals
- polymers
you can also see composites
there are also advanced materials:
- superconductors, biomaterials, nanoengineered

in metals, atoms are densely and orderly packed (especially when compared to ceramics and polymers)
metals are surprisingly strong yet ductile
- in fact, when we zoom into the texture of a metal being cut, it looks like clay, see this video: Cutting Steel Magnified and Slowed Down
metals have large amounts of non-localized electrons
- there are electrons “floating around” / electrons not bound to particular atoms
- metals being a good conductor of electricity and heat are attributable to the property of having non-localized electrons
- their “lustrous”/shiny-ness also comes from this (they are not transparent to light, explain what this means further)

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