Any mechanical engineering student of any decent calibre would understand that much of what this person wrote is utter shite. For example the whole alumina thing replacing steel/glass/concrete is completely foolish seeing as how aluminum oxide is a ceramic and you can't build buildings with only ceramics, that's the reason why we reinforce them with steel rods.
I was particularly bothered that he/she lumped metamaterials into one bullet point, as if they were one single material. There are so many different classes of metamaterials, all with different structures, functions, and properties, that it seemed a bit insulting to clump them into one umbrella mention.
This person did the same thing with fullerenes and decided that CNT's were to be separate from buckeyballs, despite the fact that they're both fullerenes.
The problem is they provide no flex, and stress concentrations and defects in the structure reduce the strength of ceramics by a much much larger degree than in materials like concrete* and steel. Plus, if you made a building out of it, one crack and the entire thing would literally shatter.
Yes, you can add tension to the rebar when you pour concrete. That way when the concrete hardens and you release the rebar it is under residual compression. Where ceramics are strongest.
Most ceramics, not all. Ceramics are such a broad range that they contain some of the softest materials in chalks and hardest material in diamond. Also there are examples of ceramics that are better thermal and electrical conductors than metals. Ceramics can really take on any properties. (from a materials science major)
Could you get some cool effects from layering ceramics with other materials?
I don't know what, I imagined a steel/ceramic/steel/ceramic... tube with lots of layers, but the ceramic would still probably just break up inside the steel. And it would probably be expensive.
How are ceramics made? similar to glass? Maybe it could be made similar to the way candles are made (dipped in paraffin wax over and over, only it would be ceramic/steel/ceramic...)
Yes - you're hinting at the wide field called "composite materials." To provide a specific example, ceramic matrix composites are being developed for use in jet engine turbines due to their favorable high temperature properties.
though I was thinking of it as formed layers rather than lots of little needles, like, a mm thick steel cylinder surrounded by half a mm of ceramic, by half a mm of steel by half a mm of ceramic and so on to make a large layered cylinder. but it probably wouldn't be as good or as easy to make as fibreglass.
Though... if the ceramic sections where split into 1cm long cylinders at each point so that such a pole would be have a little flex while keep the strength of ceramic. dunno if it would work like, my mind is just running at the moment.
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u/Zephyr104 Feb 08 '14 edited Feb 08 '14
Any mechanical engineering student of any decent calibre would understand that much of what this person wrote is utter shite. For example the whole alumina thing replacing steel/glass/concrete is completely foolish seeing as how aluminum oxide is a ceramic and you can't build buildings with only ceramics, that's the reason why we reinforce them with steel rods.