Refractory Metals: Engineering at Extreme Temperature
Introduce metals with exceptional melting points and the processing challenges that accompany them.
What makes a metal refractory
Tungsten, molybdenum, tantalum, niobium and rhenium retain strength at temperatures where common alloys soften.
Useful properties
High melting temperature, low vapour pressure and thermal stability suit furnaces, electronics, aerospace and energy systems.
Major limitations
Oxidation can be severe, room-temperature brittleness may occur, and density or cost can be high.
Processing routes
Powder metallurgy, vacuum melting, protective atmospheres and specialised joining are often required because conventional processing is difficult.
Engineering takeaway
A high melting point is only the beginning; oxidation protection, fabrication and transition temperature usually govern viability.