Inclusion/Melt Compatibility in Pure Nickel and UDIMET 720

M. Halali, D.R.F. West, M. McLean
1996 Superalloys 1996 (Eighth International Symposium)   unpublished
The inclusion content and distribution in the alloy UDIMET 720 has been studied using levitation melting. Samples of the as-cast alloy have been melted and the inclusions that concentrate on the surface have been characterised. The specific behaviour of some typical inclusions such as Al2O3, Tii, and the spine1 Al2Mg04 has been studied by deliberately adding particles onto the surface of the molten levitated sample. Light microscopy and SEM together with EDS analysis have been employed to study
more » ... the surface and sections of the solidified samples. Most of the inclusions display "nonwetting" behaviour; the few "wetting" inclusions were complex oxides of aluminitun titanium silicon, and calcium It is found that most of the wetting complex oxide inclusions are associated with sulphur. Other wetting inclusions identified (TiN, chlorides and fluorides of alkali metals and calcium) are generally secondary inclusions that form on solidification. Although sulphur is associated with most of the wetting complex oxide inclusions, the addition of 15 ppm sulphur does not significantly change the wetting characteristics of the non-wetting inclusions.
doi:10.7449/1996/superalloys_1996_457_462 fatcat:iereiu26k5cefn2ilq4pydn6li