Copper-beryllium alloy
An age-hardenable copper alloy offering extremely high strength and non-sparking properties, requiring health precautions during welding.
Beryllium copper is a tool material that can be hardened by heat treatment. That means you solution anneal it at high temperature, quench it, and then age it at medium temperature. This forms fine particles in the structure that make the material hard and strong. When welding, you have to be extremely careful because the fumes and dust are highly toxic. You definitely need good extraction right at the weld spot and suitable respiratory protection. Without that, nothing works. The material is a good heat conductor and the heat-affected zone becomes soft. So you have to work with plenty of energy and preheat the part. TIG welding with a matching filler material is the method of choice. If you need full hardness again, you must re-solution anneal, quench, and age the component after welding.