91. Enhanced performance of austenitic oxide dispersion-strengthened 316L steel: a study on ▫$Y_2O_3$▫ reinforcement and corrosion behaviourJan Pokorný, Jiří Kubásek, Črtomir Donik, David Nečas, Vojtěch Hybášek, Jaroslav Fojt, Anna Dobkowska, Irena Paulin, Jaroslav Čapek, Matjaž Godec, 2025, original scientific article Abstract: This study explores the mechanical and corrosion properties of yttria-reinforced 316L stainless steel. Powder precursor materials were prepared using mechanical alloying. Varying yttria (Y2O3) contents (1, 3, and 5 wt%) were used to assess its impact on the steel’s properties. X-ray diffraction and scanning electron microscopy confirmed the successful dispersion of Y2O3 within the matrix, with the formation of chromium carbides during spark plasma sintering (SPS). The mechanical properties, including hardness and compressive yield strength, improved with increasing Y2O3 contents, with the highest strength observed in the 316L-5Y2O3 sample. However, corrosion resistance decreased with higher yttria concentrations. The 3 wt% Y2O3 sample exhibited the highest corrosion rate due to localized corrosion in areas enriched with oxide particles and chromium carbides. Electrochemical testing revealed that carbide formation and Cr-depleted regions from SPS processing contributed to the corrosion behaviour. These findings suggest that while yttria reinforcement enhances mechanical strength, optimizing the Y2O3 content and processing methods is crucial to balance both mechanical and corrosion performance in ODS 316L stainless steel. Keywords: mechanical milling, SPS, 316L, austenitic stainless steel, yttria, ODS steel, corrosion, EPR-SL Published in DiRROS: 31.01.2025; Views: 90; Downloads: 63
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92. The distance function on Coxeter-like graphs and self-dual codesMarko Orel, Draženka Višnjić, 2025, original scientific article Abstract: Let $SGL_n(\mathbb{F}_2)$ be the set of all invertible $n\times n$ symmetric matrices over the binary field $\mathbb{F}_2$. Let $\Gamma_n$ be the graph with the vertex set $SGL_n(\mathbb{F}_2)$ where a pair of matrices $\{A,B\}$ form an edge if and only if $\textrm{rank}(A-B)=1$. In particular, $\Gamma_3$ is the well-known Coxeter graph. The distance function $d(A,B)$ in $\Gamma_n$ is described for all matrices $A,B\in SGL_n(\mathbb{F}_2)$. The diameter of $\Gamma_n$ is computed. For odd $n\geq 3$, it is shown that each matrix $A\in SGL_n(\mathbb{F}_2)$ such that $d(A,I)=\frac{n+5}{2}$ and $\textrm{rank}(A-I)=\frac{n+1}{2}$ where $I$ is the identity matrix induces a self-dual code in $\mathbb{F}_2^{n+1}$. Conversely, each self-dual code $C$ induces a family ${\cal F}_C$ of such matrices $A$. The families given by distinct self-dual codes are disjoint. The identification $C\leftrightarrow {\cal F}_C$ provides a graph theoretical description of self-dual codes. A result of Janusz (2007) is reproved and strengthened by showing that the orthogonal group ${\cal O}_n(\mathbb{F}_2)$ acts transitively on the set of all self-dual codes in $\mathbb{F}_2^{n+1}$. Keywords: Coxeter graph, invertible symmetric matrices, binary field, rank, distance in graphs, alternate matrices, self-dual codes Published in DiRROS: 31.01.2025; Views: 73; Downloads: 47
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