I am looking for a metal (alloy) that supports high temperatures (at least 1600K) and keeps its elastic property at low temperatures down to 10K. Rhenium is a good one because it does not become brittle. But it is quite expensive. Pure tungsten and molybdenum enter in the brittle regime at low temperatures. I hope that somebody knows an alloy that’s not too expensive that would make me happy!
1 Comment
Dr. Randall Barron
June 3, 2011You had asked about a metal that would withstand high temperatures (1600 K or 1330°C or 2420°F) and yet remain “elastic” (non-brittle) down to 10 K.
In many engineering applications at such high temperatures, only refractory materials retain their favorable strength properties; however, the refractories are also generally fairly brittle (have a low Charpy impact strength) at cryogenic temperatures. For example, beryllium oxide can be used up to 4000°F (2200°C or 4273 K).
There are two alloys (superalloys) that have melting points above 1600 K and retain their favorable low-temperature properties: [see ASM Metals Reference Book, 2nd ed., American Society for Materials, Metals Park, OH 44073, pp. 399-412]
[1] Haynes 25 or L-605 — a Co(54%)-Cr(20%)-Ni(10%)-W(15%) alloy
Melting temperature: 2500°F (1371°C or 1644 K)
Ultimate tensile strength at 1600°F (871°C): 47,000 psi (324 MPa)
Yield strength at 1600°F (871°C): 35,000 psi (241 MPa)
[1] Inconel X750 — a Ni(73%)-Cr(15%)-Fe(7%) alloy
Melting temperature: 2425°F (1330°C or 1603 K)
Ultimate tensile strength at 1600°F (1144 K): 34,000 psi (234 MPa)
Yield strength at 1600°F (1144 K): 24,000 psi (165 MPa)
Charpy impact strength at –300°F (–184°C or 88.7 K): 37 ft-lbf
(which is a good impact strength value at low temperatures)
I do not have data about the cost of these materials; however, you may contact the International Nickel Company for cost information on Inconel X750. Also, they may have some other high-temperature alloys that they have developed in recent years that would meet your needs.