3 ms·

Actually, they all do.

by kragen 2y ago

fc417fc802 2y ago
Depends on what is meant by high strength. Silverware is a fair point that hadn't occurred to me. Handrails is an interesting one but I suspect it's more cost effective to place a thin contact surface on top of something cheap. The others I'm not so sure about. I think you'd have corrosion issues with water tanks and bacterial issues there are easily addressed by regulating temperature. And why would heat exchangers require particularly high strength? Since when are those a structural component? In any case as you said electroplating something cheap is probably the way to go.
- kragen 2y ago
  Recuperator-type heat exchangers need high-strength materials because both the strength of a wall and its thermal resistance are proportional to its thickness. So, if you can magically make copper five times stronger, you can make it one fifth as thick, cutting its thermal resistance by a factor of 5 and getting a much better heat exchanger. As for water tanks, regulating temperature is not always "easy", and a major reason copper is used for water pipes is its great resistance to corrosion. In this case apparently it will be more expensive than the same mass of stainless, but it's apparently also stronger than stainless, so maybe you can use less of it, making it cheaper again.
  - fc417fc802 2y ago
    Fair point about water pipe corrosion, my mistake. Although thinking about it more carefully what is strength saving you there other than cost? This material is going to be at least a 10x cost premium judging by the elemental composition. And if we're talking household temperatures I expect there are polymer coatings that would work better. The heat exchanger point is interesting. However doesn't stainless already lose out to 3D printed aluminum for the sort of applications where the optimization is worth the cost? This material is even heaver than steel and substantially more expensive. It's tangential but I wonder how amenable to 3D printing this material will prove to be.
    - kragen 2y ago
      https://news.ycombinator.com/item?id=43816979 https://news.ycombinator.com/item?id=43816979 suggested that the raw materials imply about a 6x cost increase over stainless, which is less than 10x. I haven't done the numbers myself. High-energy cryogenic ball milling of 10 grams for four hours in a continuous flow of liquid nitrogen under an argon atmosphere with <1ppm oxygen (https://www.science.org/action/downloadSupplement?doi=10.1126%2Fscience.adr0299&file=science.adr0299_sm.pdf https://www.science.org/action/downloadSupplement?doi=10.112...) sounds expensive, but maybe they only did it that way because it was a low-risk way to ensure the alloying worked with the lab equipment they had on hand, not because it's the cheapest way to make the material. Hopefully cheaper ways are found. I'm no expert in heat exchangers, but my calculations suggest 3-D printing is or will be an enormous boost there, and may reverse the gradient of merit for wall material thermal conductivity, favoring good thermal insulators over good thermal conductors like copper and aluminum. As for aluminum, it is only suitable for low temperatures.
      - fc417fc802 2y ago
        6x for the raw materials before you account for the production process. I'm curious. What mechanism would lead to an insulator being favored in a heat exchanger? Fair point about aluminum and temperature. As a layman an engine block is high temperature to me. I guess this would be extremely useful for more exotic stuff.
        kragen 2y ago
        If the fluid path through the heat exchanger is very short and the contact area is very large, preventing lengthwise conduction of heat from one end of the fluid path to the other, rather than getting enough conduction between the fluids, should become the performance-limiting factor. See https://dercuano.github.io/notes/capillary-heat-exchanger.html https://dercuano.github.io/notes/capillary-heat-exchanger.ht.... I could be wrong about this, but I didn't just make it up; I got it from Lingai Luo's book on heat and mass transfer intensification, which hopefully I've understood correctly.
kergonath 2y ago
No, they don’t. The force a man can apply does not require "high strength" materials to withstand. They don’t need high temperature performance, either. Seriously, we don’t need superalloy spoons. When we’re talking about advanced materials, "high strength" means hundreds of MPa and "high temperature" is beyond 500°C (and more depending on the application).
- kragen 2y ago
  Any material can withstand the force a man (or a woman) can apply if you make it thick enough. Contrapositively, if you make it too thin, it can't. So sign me the fuck up for the superalloy spoons, but hold the nickel, please. (It would be excellent to be able to clean my silverware by firing it in a kiln, though with a copper alloy I'd probably have to scrub off the verdigris.)
  - kube-system 2y ago
    304 stainless is already strong enough that you could make a durable spoon thin enough that it would be painful to use. And it is cheap.
    - kragen 2y ago
      8–11% nickel, not antibacterial, and five times weaker than this CuLiTa alloy in the annealed state. Thin out the middle and leave thick edges to avoid pain. None of this is an option with this new alloy unless someone finds a cheaper way to make it and probably some kind of beryllium-copper-like precipitation hardening process so you can form it.
      - fc417fc802 2y ago
        > Thin out the middle and leave thick edges to avoid pain. Ok but if you do that then what is the point of the exercise? I thought fancy flatware was thin because of the appearance. If the edges are thick doesn't that defeat the purpose? The equivalent thickness being something like 5x stronger is of course the benefit here. I don't think price is an issue for high end home use items. Rich people buy far weirder and more expensive things.

Actually, they all do.

by kragen 2y ago

Actually, they all do.

Depends on what is meant by high strength. Silverware is a fair point that hadn't occurred to me. Handrails is an interesting one but I suspect it's more cost effective to place a thin contact surface on top of something cheap. The others I'm not so sure about. I think you'd have corrosion issues with water tanks and bacterial issues there are easily addressed by regulating temperature. And why would heat exchangers require particularly high strength? Since when are those a structural component? In any case as you said electroplating something cheap is probably the way to go.

kragen 2y ago
Recuperator-type heat exchangers need high-strength materials because both the strength of a wall and its thermal resistance are proportional to its thickness. So, if you can magically make copper five times stronger, you can make it one fifth as thick, cutting its thermal resistance by a factor of 5 and getting a much better heat exchanger. As for water tanks, regulating temperature is not always "easy", and a major reason copper is used for water pipes is its great resistance to corrosion. In this case apparently it will be more expensive than the same mass of stainless, but it's apparently also stronger than stainless, so maybe you can use less of it, making it cheaper again.
- fc417fc802 2y ago
  Fair point about water pipe corrosion, my mistake. Although thinking about it more carefully what is strength saving you there other than cost? This material is going to be at least a 10x cost premium judging by the elemental composition. And if we're talking household temperatures I expect there are polymer coatings that would work better. The heat exchanger point is interesting. However doesn't stainless already lose out to 3D printed aluminum for the sort of applications where the optimization is worth the cost? This material is even heaver than steel and substantially more expensive. It's tangential but I wonder how amenable to 3D printing this material will prove to be.
  - kragen 2y ago
    https://news.ycombinator.com/item?id=43816979 https://news.ycombinator.com/item?id=43816979 suggested that the raw materials imply about a 6x cost increase over stainless, which is less than 10x. I haven't done the numbers myself. High-energy cryogenic ball milling of 10 grams for four hours in a continuous flow of liquid nitrogen under an argon atmosphere with <1ppm oxygen (https://www.science.org/action/downloadSupplement?doi=10.1126%2Fscience.adr0299&file=science.adr0299_sm.pdf https://www.science.org/action/downloadSupplement?doi=10.112...) sounds expensive, but maybe they only did it that way because it was a low-risk way to ensure the alloying worked with the lab equipment they had on hand, not because it's the cheapest way to make the material. Hopefully cheaper ways are found. I'm no expert in heat exchangers, but my calculations suggest 3-D printing is or will be an enormous boost there, and may reverse the gradient of merit for wall material thermal conductivity, favoring good thermal insulators over good thermal conductors like copper and aluminum. As for aluminum, it is only suitable for low temperatures.
    - fc417fc802 2y ago
      6x for the raw materials before you account for the production process. I'm curious. What mechanism would lead to an insulator being favored in a heat exchanger? Fair point about aluminum and temperature. As a layman an engine block is high temperature to me. I guess this would be extremely useful for more exotic stuff.
      - kragen 2y ago
        If the fluid path through the heat exchanger is very short and the contact area is very large, preventing lengthwise conduction of heat from one end of the fluid path to the other, rather than getting enough conduction between the fluids, should become the performance-limiting factor. See https://dercuano.github.io/notes/capillary-heat-exchanger.html https://dercuano.github.io/notes/capillary-heat-exchanger.ht.... I could be wrong about this, but I didn't just make it up; I got it from Lingai Luo's book on heat and mass transfer intensification, which hopefully I've understood correctly.

kergonath 2y ago

No, they don’t. The force a man can apply does not require "high strength" materials to withstand. They don’t need high temperature performance, either. Seriously, we don’t need superalloy spoons. When we’re talking about advanced materials, "high strength" means hundreds of MPa and "high temperature" is beyond 500°C (and more depending on the application).

kragen 2y ago
Any material can withstand the force a man (or a woman) can apply if you make it thick enough. Contrapositively, if you make it too thin, it can't. So sign me the fuck up for the superalloy spoons, but hold the nickel, please. (It would be excellent to be able to clean my silverware by firing it in a kiln, though with a copper alloy I'd probably have to scrub off the verdigris.)
- kube-system 2y ago
  304 stainless is already strong enough that you could make a durable spoon thin enough that it would be painful to use. And it is cheap.
  - kragen 2y ago
    8–11% nickel, not antibacterial, and five times weaker than this CuLiTa alloy in the annealed state. Thin out the middle and leave thick edges to avoid pain. None of this is an option with this new alloy unless someone finds a cheaper way to make it and probably some kind of beryllium-copper-like precipitation hardening process so you can form it.
    - fc417fc802 2y ago
      > Thin out the middle and leave thick edges to avoid pain. Ok but if you do that then what is the point of the exercise? I thought fancy flatware was thin because of the appearance. If the edges are thick doesn't that defeat the purpose? The equivalent thickness being something like 5x stronger is of course the benefit here. I don't think price is an issue for high end home use items. Rich people buy far weirder and more expensive things.