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