I am quoting a job for NASA that requires a triple helical set of holes of
varying pitch and varying diameter to a blind depth. The alloy is
samarium-dysprosium-ytterbium, which normally wouldn't present a problem,
but they increased the dysprosium on this job to 16%, which of course
changes the eutectic structure from face centered to body centered. As you
all know this prohibits the use of fluoroscopy in the process. I am
concerned about the Guinier-Preston zone, which I'm sure you all realize is
the preprecipitation domain in a supersaturated metallic solid solution. I
feel this may result in a pseudobinary system or ternary alloy system.
Should I suggest they use a quasibinary system of linear composition which
would exhibit congruent melting, wherein all equilibriums, at all
temperatures, involve only phases having compositions occurring in the
linear series?

Thank You
Dr. Dixon
Tech. Director
Fermi Laboratory