Effects of Rare Earth on Austenite-Ferrite Phase Transformation in a Low-Carbon Fe-C Alloy

The influence of rare earth (RE) elements on austenite-ferrite phase transformation in Fe-0.14%C alloy has been investigated by in situ observing the nucleation, growth and morphology of ferrite using high temperature laser scanning confocal microscopy, and controlled atmosphere decarburization experiments. It is found that under the low-oxygen condition in steel, trace RE addition can significantly influence the nucleation, morphology and growth of ferrite in Fe-0.14%C alloy by the combined effects of RE slowing down the carbon diffusion and decreasing grain boundary energy by segregating at grain boundaries. This research provides evidences of adjusting the phase transformation and improving the mechanical properties of steels by RE addition.

Automated summary

It is found in this study that under low-oxygen conditions, the addition of trace rare earth elements can significantly influence the nucleation, morphology, and growth of ferrite in Fe-0.14%C alloy, by slowing down carbon diffusion and decreasing grain boundary energy. This research provides evidence for adjusting phase transformation and improving the mechanical properties of steels through the addition of rare earth elements.