Structure Evolution of Fe-7.5at.Ni Alloy Thin Strips under Near-rapid Solidification Conditions

摘要

In this paper, the structure evolution of Fe-7.5at.%Ni thin strips under near-rapid solidification conditions was investigated. One-dimensional (1D) heat transfer model was used to calculate the cooling rate of thin strips. The calculated results showed that the decrease of distance from the surface, made the effective heat transfer increase sharply, which led to a higher cooling rate. Moreover, the experimental results showed that the size of the columnar crystals increased clearly by the increase of the distance from the surface, and equiaxed grains appeared when the distance was above 0.75mm. In addition, it is indicated that even the strip thickness changed from 1.0mm to 2.0mm, the size of columnar crystals didn't change much in regions which have the same distance from the surface.