I was reading in Nasa Tech Briefs about Electron Beam Melting (EBM)
being used to make near net and net parts out of titanium alloys.
Other alloys have been used to make parts, aluminum being one, but the
titanium alloys and CP titanium seem to be the predominant metals
being used. After the parts come out of the EBM machine they are
subjected to Hot Isostatic Pressing (HIP). the HIP process closes up
any micropores in the EBM fashioned part. When an aluminum alloy is
cast and then run through a rolling mill the structure is changed
significantly. This wrought alloy behaves much differently than the
same alloy as cast . My question is whether the HIP process changes
the alloy so that it behaves more like a wrought alloy or if basically
remains the same, just denser.
Thanks,
Eric

On Fri, 29 Aug 2014 09:04:35 -0700, wrote:

I was reading in Nasa Tech Briefs about Electron Beam Melting (EBM)
being used to make near net and net parts out of titanium alloys.
Other alloys have been used to make parts, aluminum being one, but the
titanium alloys and CP titanium seem to be the predominant metals
being used. After the parts come out of the EBM machine they are
subjected to Hot Isostatic Pressing (HIP). the HIP process closes up
any micropores in the EBM fashioned part. When an aluminum alloy is
cast and then run through a rolling mill the structure is changed
significantly. This wrought alloy behaves much differently than the
same alloy as cast . My question is whether the HIP process changes
the alloy so that it behaves more like a wrought alloy or if basically
remains the same, just denser.
Thanks,
Eric

HIPping just squeezes the metal. It doesn't do a lot to the
microstructure.

However, there are wide variations in the microstructure of different
alloys and their response to cold- or warm-working, aluminum being a
strong example. The alloys that we use in wrought form, such as 5052
and, to a lesser extent, 6061, are like frozen chewing gum in their
cast form. They need to be worked to develop useful properties.

That being said, 6061 can be cast, even at home. It's just not going
to be as strong as the wrought form.

If you're interested in EBM, you'll find the emerging business of
laser-melting to be interesting. It's a "3D printing" process with
powdered metal, but, unlike sintering, it achieves close to 100%
density.

--
Ed Huntress