Beryllium copper spark-free tools (mining application)

Tom's own beryllium copper crescent wrench ($130) as a teaching prop. Used in methane-bearing mines because high thermal conductivity prevents the frictional hotspot that would ignite gas. Properties: well over 1 GPa strength, 150–180 ksi, hardness comparable to a steel wrench, but ten times the cost.

So you can harden aluminum by quenching and tempering. You can harden steel by quenching and tempering. There are some stainless steels you can harden, we call them precipitation hardenable — what a clever name we have. Copper alloys — this is my beryllium copper crescent wrench, cost about $130, you can buy one yourself. Anyone remember from last term why we use beryllium copper tools? You can buy a whole toolset, all kinds of tools, for a thousand dollars instead of $400 out of steel.