AUTHOR=Zheng Yuehong , Zhao He , Zhang Na , La Peiqing , Shi Yu , Zhu Min , Zhan Faqi 

TITLE=Effect of Excessive Fe2O3 on Microstructural Evolution of Micro/Nanocrystalline 2205 Duplex Stainless Steel Prepared by Aluminothermic Reaction

JOURNAL=Frontiers in Materials

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2020.00119

DOI=10.3389/fmats.2020.00119

ISSN=2296-8016

ABSTRACT=<p>It is one of the effective ways to obtain excellent comprehensive performance of 2205 duplex stainless steel (DSS) to adjust the volume ratio and grain size of α and γ phases. In the present paper, 2205 DSSs with micro-nano structures were successfully prepared by aluminothermic reaction under appropriate Fe<sub>2</sub>O<sub>3</sub> excess conditions, and the formation mechanism of micro/nano structures was studied from the aspects of the preparation process, element equivalent, and residual Al content. Here, the Cr<sub>eq</sub>/Ni<sub>eq</sub> ratio of the 2205 DSS is 2.09, indicating that the solidification mode belongs to mode F, that is, L → L + α→α→α + γ. The residual Al content and the volume percentages of α and γ phases and their grain sizes can be controlled by reasonably adjusting the excess percentage of Fe<sub>2</sub>O<sub>3</sub>. When the excess percentage of Fe<sub>2</sub>O<sub>3</sub> is 5.0%, the volume percentages of α and γ phases reach the minimum and maximum values, respectively. However, when there is a large amount of unreacted Al in the alloy or an inappropriate excess percentage of Fe<sub>2</sub>O<sub>3</sub> for preparation, only the α phase is contained in alloys.</p>