Analysis of size distributions of primary oxide inclusions in Fe-10 mass pct Ni-M (M = Si, Ti, Al, Zr, and Ce) alloy

The planar and spatial size distributions of primary oxide inclusions were measured in an Fe-10 mass pct Ni alloy on deoxidation with 0.2 mass pct M ( M = Si, Ti, Al, Zr, and Ce). It was found that the size distribution of inc lusions obtained at a certain magnification in microanalysis was accurate o nly in a limited range of particle size, due to the limit of observation fo r the minimum size and observed area. The inclusion characteristics such as mean spatial diameter, (d) over bar(V), the number of particles per unit v olume, N-V, and the volume fraction of particles, f(V), were estimated from the size distribution obtained in a planar cross section by using differen t methods. The (d) over bar(V) and N-V values and the size distribution est imated from the cross-sectional method using different magnifications were compared with those obtained from the extraction method. The f(V) values ob tained from size distribution were found to be considerably greater than th ose from chemical analysis of oxygen or metal element as inclusion. Further more, the behavior of the size distribution as a function of holding time a t 1873 K is discussed.