Precipitate behavior in nitrogen-containing CoCrNi medium-entropy alloys

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>The effect of nitrogen addition toward nitride precipitate formation and the corresponding behavior in a medium-entropy alloy system of N-CoCrNi was investigated. It was observed that the addition of N induced the formation of a Cr- and N-rich precipitate of Cr<SUB>2</SUB>N. Cr<SUB>2</SUB>N and the face-centered cubic (FCC) matrix in the N-CoCrNi system exhibited a Kikuchi orientation relation in the {111}<I>γ</I>//{0001}Cr<SUB>2</SUB>N plane and ⟨110⟩<I>γ</I>//⟨ 1 1 ¯ 00 ⟩Cr<SUB>2</SUB>N direction, where Cr<SUB>2</SUB>N was observed to be semi-coherent with the FCC matrix. The presence of Cr<SUB>2</SUB>N was also observed to contribute in the hindering of grain coarsening via Zener pinning pressure. The distribution of finer and higher fraction of Cr<SUB>2</SUB>N in the lower annealing temperatures of N-CoCrNi contributed more toward higher Zener pinning pressure compared to the coarser and lower fraction of Cr<SUB>2</SUB>N in the higher annealing temperatures, which subsequently affected grain growth during the annealing treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of nitrogen addition in CoCrNi medium-entropy alloy was investigated. </LI> <LI> Cr<SUB>2</SUB>N precipitate was formed along with the face-centered cubic matrix. </LI> <LI> A Kikuchi crystal orientation relation was observed between the Cr<SUB>2</SUB>N and the matrix. </LI> <LI> Cr<SUB>2</SUB>N precipitate contributed in Zener pinning pressure. </LI> <LI> These caused the formation of significantly finer grain size in N-CoCrNi than CoCrNi. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>