A study of the effect of induction-vacuum-melting practice on the high-temperature properties of 55Ni-20Cr-15Co-4Mb-3Ti-3Al alloy revealed that a major variable was the type of ceramic used as a crucible. Reac¬tions between the melt and magnesia or zirconia crucibles apparently increased high-temperature properties at 1,600° F by introducing small amounts of boron or zirconium into the melts.nHeats melted in alumina crucibles had relatively low rupture life and ductility at 1,600° F and were prone to crack during hot-working. Apparently this resulted from lack of derivation of boron or zirconium from the crucible.
展开▼
