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darryl
02-25-2003, 05:02 AM
I've read about metals being 'sprayed' on to a rotating drum that is cooled. The metal is cooled so quickly that crystals don't have time to form. The result is a material that has enhanced qualities for use in transformers, motors, etc. I think some of those samarium cobalt model electric motors are using it. My question is has anyone had any experience working with materials made this way, and what might some other uses be. It seems to me that it could be machined very easily, and acquire a very good surface finish.

wierdscience
02-25-2003, 09:37 AM
I have had limited experience with the alloys in question we machined some bushings that were made from a nickel/cadnium alloy nasty stuff to cut these two are things that normally don't go together except they were sintered in a press.The people that supplied the bushings gave us some literature on the process and it involed pouring the molten metal onto a water cooled ni-hard disc that was spun up at 10,000 in an argon atmosphere.This produced metalic nodules that could be mixed to the desired compostion and the sintered in a heated die to form an alloy that had lets say "designer" properties the primary draw backs where expense these little bushings 1/2od .472id 1.340 long cost about $90.00 each to make and they were extremely brittle and difficult to machine.They were going to be a experiment in an aerospace assembly but last I heard they were replaced with alluminum bronze!$2.75 each!I have had a lot off experience with sintered products of the normal compostions with mixed results.

Thrud
02-26-2003, 01:55 AM
darryl:
Can't help you there.

There are lots of neat things happening in the metalworking world and new materials being worked on every day. Companies like Iscar, Kennametal, and Sandvik are constantly coming up with new innovations.

yf
02-26-2003, 11:49 AM
About 15 years ago Popular Science ran an article about the development of these types of metals. They metioned that the metals took on glasslike properties. They were also extremely difficult to machine. I remember something like only one tenth the life of punches and dies.

They called them supercooled metals as the molten metal was cooled at a rate of a million degrees per second.

They were supposed to use supercooled iron to make a new generation of super efficient transformers, but they were having trouble punching the laminations back then.

I can't recall any other article about it since.

Endmill
02-26-2003, 09:27 PM
There are a number of types of materials which are called met-glass, which are made by rapid cooling. Allied chemical used to be a major supplier. Some compositions have have extremely high magnetic permeabilities and are used in transformers, shielded enclosures, magnetometers, and as "shop lifting" tags. The material is available in sheet form and is quite hard. What I have seen or worked with resembles stainless shim stock.
Bob

Herb Helbig
02-26-2003, 10:06 PM
A late, lamented colleague, Sigurds Arajs, had graduate students doing research on met-glass. For his work he built a massive copper wheel about 6 or 8 inches in diameter and about an inch thick that was shrunk fit onto a steel shaft that was mounted in bearings and spun at high speed. Molten metal, an iron alloy I think, was dropped onto the wheel from a small furnace. A thin ribbon of the metal was thrown across the lab, and collected for analysis - mostly magnetic and electric properties. I did the shrink fit calculations to make sure the elasticity of the copper could provide enough centripetal force to keep the copper in contact with the steel shaft at the RPM required. Unfortunately, I was busy with other things and didn't think of trying to machine the met-glass.

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darryl
02-27-2003, 04:32 AM
Hmm, it's looking like it's not a machinist's dream material. I can't quite wrap my mind around the fact that it's difficult to punch, shear, etc, yet it's magnetically 'soft', or permeable. That somehow suggests that it would be mechanically soft as well.