Solidification structure and segregation in iron-chromium-nickel alloys.

Abstract

The equilibrium distribution coefficients for chromium and nickel in the unidirectionally solidified iron-chromium-nickel alloys containing 5 to 20wt%Cr and 5 to 30wt%Ni were evaluated on the basis of the microsegregation ratio for the alloying elements. The solidification paths calculated from the values of the coefficients were in good agreement with those obtained experimentally.The primary arm spacing in the alloys was proportional to the square root of the inverse cooling rate. The alloys whose primary crystal is δ had slightly larger primary arm spacing than those forming γ as the primary phase. The secondary arm spacing measured for some alloys was inverse as the 0.4 to 0.5 power of cooling rate and was independent of the alloy composition.