Metrics:
- Strength (UTS)
- Ductility (max elongation)
- Thermal conductivity
- Radiation resistance / embrittlement (ductile to brittle transition volume fraction?)
- Activation: Radioactivity time constant?
- High melting temperature
- Manufacturability ($/kg or tons/year)
- Sputtering (erosion rate?)
- This applies both the first wall and to the diverter!