Casting problem with 4 elements

Any idea about the respective quaternary phase diagrams?

Does it evaporate? Or how does it separate?

Michael Dahms

If you can use powder metallurgy techniques to do the final forming then the FFC process might solve your problem. It is not yet a cheap process and some experimental process refinement will be needed because the Mg will still present problems.

If this is a known alloy how has it been made before? If not then how do you know this is the alloy you want?

Att M.D.

It did not evaporate. It is on the surface of casting. The metals melt well. But after pouring, magnesium separates out to the surface.

The only direction on how to make the solution was given as : ...start melting from the highest to the lowest by dropping down, then add, then drop down again. No vacuum is to be used. Before adding the Mg, drop down as low as possible and not let the materials solidify.

As I am not at all specialised in this field, I have no idea about the quaternary phase diagrams.

Thanks for your time,

johnny

Michael Dahms schreef:

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As it is only a small ( at this moment ) try-out, big expense(s) cannot be afforded.

The composition has been "back-engineered" from a small existing piece. Without actually known how this has been accomplished. The only main idea behind the mix, is the special magnetic property this material is supposed to have, in one or another way ( not sure what, but the castings are meant to make further research possible in this direction ).

johnny

johnny

Since several of the metals you have chosen form intermetallic compounds it would not be simply a homogenous mixture either during melting (depending on temperature) and certainly not after solidification. The alloys might, at best, be very brittle, even if they do not separate into layers during solidification.

Bob

You should check the phase diagrams. You should also analyze the material that you say is separating out. It is probably an intermetallic. Also, what temperature are you holding the melt? Are you sure it's high enough to dissolve the intermetallic?

The following is a small piece of an email I got from ASM today, don't know if this will help you or not. :/

The only metallurgy I really know is high carbon and tool steels as it relates to edge holding knives. :)

Self taught just for the fun of it, see? :)

Alvin in AZ (knife knut) ps-

-------------------------------------------------------------- ASM International E-Newsletter Volume 6, Issue 26, Wednesday, June 28, 2006

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NEWS FROM ADVANCED MATERIALS & PROCESSES

Continuous rheo-conversion casts magnesium, aluminum

Magnesium alloy AZ91D and aluminum alloy 206 have been processed via the continuous rheo-conversion process (CRP) in a study by SPX Corp., Contech Division, Mishawaka, Ind..; and the Metal Processing Institute of Worcester Polytechnic Institute, Worcester, Mass. Results showed that CRP can consistently produce "ideal semi-solid structures with small spheroidized primary particles free of entrapped liquid." The process was studied because of the possibility that it could produce high-quality, low-cost feedstock for the semi-solid casting process utilized by the automotive industry.

In the CRP process, two superheated liquids are allowed to flow through a reactor that enables high nucleation rate and forced convection of the two streams. The slurry can then solidify completely in a cold receiving crucible. It is reheated to the semi-solid region, or it can be partially solidified in a heated crucible and directly sampled.

Much more information is available in "Semi-Solid Casting of Magnesium and Aluminum Alloys via the CRP (Continuous Rheo- Conversion Process)," by R. DasGupta and Z. Brown, SPX Corp.; and Q.Y. Pan and W.J. Bernard, Metal Processing Institute, WPI. Paper No. 2006-01-0509, it was presented at the 2006 SAE World Congress.

For more information: R. DasGupta, SPX Corp., 520 South Byrkit Street, Mishawaka, IN 46544; tel: 574/258-6175;

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If you have any questions for ASM International, please call our Customer Service Center at 1-440-338-5151 ext. 6 or email mailto: snipped-for-privacy@asminternational.org