Earlier quoted context omitted.
Here's a technical explanation.[1] But here's an example of triggering crystal formation in a supersaturated solution.[2] Classic high school chemistry experiment. Dropping a solid crystal into the supersaturated solution causes the whole liquid to turn into a solid in seconds. That's the basis of single-crystal casting. The solidification process relies on operating very close to the melting point of the material. T…
Where's [2]? Thanks!
Rolls-Royce’s single-crystal turbine blade casting foundry
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Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#52The high-pressure turbine is, in more ways than one, one of the the highly optimised inner-loops of the modern world.
Care to expand on that analogy?
Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#53Not to take away from the engineering marvel that these parts and process represent, but the timing of this article is interesting - seems PR related. I recently read about problems ANA faced with Rolls Royce engines, specifically the turbine blades failing. There have been at least 3 incidents of engine failure, flights have been cancelled an all 787 engines have to be retrofitted with new blades. http://www.reuters…
Also don't forget the A380 RR disaster-that-was-prevented-by-sheer-luck.
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Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#54It's really incredible to imagine blazing hot combustion products, and these blades surviving in that environment for any length of time. Now I feel as though I have a bit of a better understanding of how that comes to pass.
Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#55Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#56Earlier quoted context omitted.
Also don't forget the A380 RR disaster-that-was-prevented-by-sheer-luck.
???
Guessing he's referring to this: https://en.wikipedia.org/wiki/Qantas_Flight_32
Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#57I had the chance recently to see the Mayor of the City of London's (the strange city-within-a-city bit of London) two Rolls Royce's they keep for formal occasions up close. They are super rare (only ~400 ever made), worth a whole lot of money and looked amazing . I'm not a car person but you can't help but feel a shiver when you see a car like that. The engines where the same as the ones they used in the Spitfire fig…
On jury service at the Old Bailey by any chance?
Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#58One other surprising thing about turbofans is that the majority of their thrust is produced by the huge main fans (the blades which are visible as you stand and look at the front of the engine) simply dragging the aircraft through the air as with a turbo-prop (or boat prop). The ultra-high pressure compression and burning stage (being discussed here) produces only 30-45% of direct thrust but clearly powers the spinning of the large components.
My father-in-law started at RR as a graduate trainee and left 40+ years later as its' longest serving member of staff, CEO and Chairman. he took me on tours of these plants when I first met my wife which was an unbelievable treat.
Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#59Fantastic read! Now why can't all technical and scientific journalism hold itself to this standard? Instead of making the prevailing assumption that your average reader has the I.Q. of a parsnip and the scientific literacy of a kindergartener ;) Have always felt single-crystal foundaries could be a great driver for building low Earth orbit microgravity factories. There has been extensive research in the labs on ISS d…
How do you benefit form zero gravity in casting?
Re: Rolls-Royce’s single-crystal turbine blade casting foundry
#60I'd like to note few things: single crystal is the best way to fight creep, but that's it. This is very specific problem with very specific solution. For most engineering problems you would prefer high fatigue strength or high ductility. Single crystal is poor for both.
Another thing is that single crystal metal is very distinct from amorphous metal. Neither has grain boundaries, but single crystal is very strictly ordered structure while amorphic is completely disorganized. As a result, single crystal tolerates high temperatures extremely well, while amorphic is worse than regular metals.
Both are distinct from powder metallurgy. Which in turn has very high amount of grain boundaries.
Interesting thing here is that in regular steel, the grains are single crystals while the boundaries are often amorphic. So in a way you have "composite" material. (It's not technically composite, because both substances have same elements in same proportions.)