Phase, Composition and Structure Changes of CoCrNi-Based Concentrated Alloys Resulting from High Temperature Oxidation

In this work, CoCrNi, FeCoCrNi and CoCrFeMnNi concentrated alloys with a Y-Ti oxide particle dispersion were prepared by mechanical alloying and Spark Plasma Sintering. The alloy consists of an FCC Ni-based matrix with a Y-Ti oxide dispersion and additional phases of Cr<sub>23</sub>C<...

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Bibliographic Details
Main Authors: Monika Vilémová, Hynek Hadraba, Zdeněk Weiss, František Lukáč, Štefan Csáki, Zdeněk Chlup, Jiří Matějíček, Tomáš Chráska
Format: Article
Language:English
Published: MDPI AG 2020-05-01
Series:Materials
Subjects:
Online Access:https://www.mdpi.com/1996-1944/13/10/2276
Description
Summary:In this work, CoCrNi, FeCoCrNi and CoCrFeMnNi concentrated alloys with a Y-Ti oxide particle dispersion were prepared by mechanical alloying and Spark Plasma Sintering. The alloy consists of an FCC Ni-based matrix with a Y-Ti oxide dispersion and additional phases of Cr<sub>23</sub>C<sub>6</sub> and Cr<sub>2</sub>O<sub>3</sub>. The effect of Fe, Mn, and Y-Ti oxide particles on the formation of oxide scales and the composition of the adjacent CoCrNi and FeCoCrNi alloys was studied. It was found that alloys without Mn in their composition form a protective Cr<sub>2</sub>O<sub>3</sub> scale. The Cr<sub>23</sub>C<sub>6</sub> particles provide an alternative mechanism for balancing the chromium loss during the oxidation. Y and Ti from the oxide particles participate in the formation of the protective oxide scales. Fe promotes Y and especially Ti diffusion through the Cr<sub>2</sub>O<sub>3</sub> scale, resulting in the formation of Ti-depleted regions in the alloy. The findings will serve for the further development of these new materials.
ISSN:1996-1944