EFFECT OF SULFUR ON THE SOLIDIFICATION AND SEGREGATION IN INCONEL-718ALLOY

The effect of sulfur on the solidification and segregation in Inconel 718 alloy was studied. Sulfur is extremely depleted in the matrix, sli ghtly dissolved in the Laves phase and NbC, and seriously segregated a s sulfides. Except for the needle-like Y-phase ((Nb, Ti)(2)SC), a glob ular sulfide was newly found to form following the precipitation of th e Laves phase. The precipitation of sulfides is speculated to be avoid ed when the sulfur content is low enough and most of the sulfur in the alloy is dissolved in the Laves phase. Sulfur has diverse effects on the solidification behavior of the alloys; the mechanism is discussed in the text.