Mass-based circularity indicators, such as ISO 59020:2024, quantify material recovery as a share of total throughput but do not account for chemical composition or functional performance, as a consequence of their sector-agnostic design. In copper metallurgical systems, trace tramp elements (e.g., As, Sb, Bi, Fe, Sn, Ni) present in WEEE-derived scrap, anode slimes, and refinery residues can significantly reduce electrical conductivity. Even at nominal purities of ≥99.7 wt.% Cu, conductivity may drop to 85.0–88.0% IACS, as illustrated by selected reported cases—a level of functional degradation that remains undetected by mass-based accounting. Analysis of Grade A cathode standards (EN 1978:2022, LME Cu-CATH-1, ASTM B115-10:2021) shows that impurity limits as low as 2 ppm (Bi) constrain the achievable share of secondary feed in closed-loop recycling. For a specific flash-smelting–refinery configuration, modeling indicates that secondary feed shares above approximately 30% may lead to impurity accumulation beyond the stated specification constraints unless low-impurity primary copper is introduced. This study introduces the Quality-Adjusted Circularity Indicator (QACI), a conceptual, specification-constrained indicator framework that applies a dilution factor f_dil derived from a binary blending mass balance to adjust ISO 59020:2024 inflow-based circularity indicators using a feed-composition blending constraint anchored to Grade A specification limits. The QACI functions as a feed-composition screening indicator operating at the anode blending stage and does not represent a correction of the full electrorefining system. Parametric scenario analysis across six stylized impurity configurations shows that, at identical mass-based circularity (C_mass = 25%), the QACI ranges from 7.1% to 25.0%. This corresponds to a 1.3- to 3.5-fold difference between the mass-based and quality-adjusted indicator values under the stated feed-composition assumptions, illustrating the potential overestimation introduced when feed-quality constraints are not considered. This ratio quantifies the divergence between two indicator values under stylized conditions and should not be interpreted as a directly measured fold-difference in actual loop-closure performance. Positioned within the ISO 59020:2024 Annex C complementary method space, the QACI is positioned as a first-order screening approach of existing circularity metrics that may inform future research discussion of quality-differentiated approaches in EU secondary metals policy.

In this work, the hardness homogeneity of aluminum Al-Mg alloy slabs produced with semicontinuous casting process from 6 different charges was investigated. The evaluation of hardness homogeneity was carried out on the front and rear cross-sectional plates of the slabs at locations determined by a statistical design of experiments (“Latin square”). Previous studies have shown that the hardness depends on the location of the test and also correlates with the technological conditions. Therefore, hardness measurements were carried out according to the Vickers method at different distances from the edge of the plate: 1 mm, 2 mm, 5 mm, 10 mm and 20 mm. The hardness of the tested aluminum alloy plates decreases in both the height and width of the plate from the edges to the center, following the polynomial behavior. The hardness decreases from the edge up to a distance of 5 mm, after which the hardness equalizes for both for the slabs’ fronts and rears.

Поршни двигателей внутреннего сгорания в основном изготавливаются из сплавов на базе системы Al–Si (силумины). В высоконагруженных дизельных двигателях в качестве держателей колец на рабочей поверхности поршней предусмотрены канавки для колец, которые изготавливают из сплавов на основе железа, например, чугуна. Таким образом, в процессе работы двигателя в поршневой части работает как силумин, так и легированный чугун, т.е. образуется согласованно работающая металлическая пара на основе сплавов алюминия и железа. Если в паре связующий слой не образуется, то на канавках, где расположены поршневые кольца, образуется дефект, и двигатель выходит из строя. В настоящем исследовании проведен анализ формирования связующего слоя в паре «канавка поршня–кольцо». Результаты исследования показали механизм взаимодействия между двумя сплавами. The pistons of internal combustion engines are mainly made of alloys based on the Al–Si system (silumins). In heavily loaded diesel engines, grooves for rings are provided as ring holders on the working surface of the pistons, which are made of iron-based alloys, such as cast iron. Thus, during the operation of the engine, both silumin and alloyed cast iron work in the piston part, i.e. a metal pair working in concert on the basis of aluminum and iron alloys is formed. If a bonding layer is not formed in a pair, then a defect forms on the grooves where the piston rings are located, and the engine fails. In the present study, an analysis was made of the formation of a bonding layer in the “piston groove–ring” pair. The results of the study showed the mechanism of interaction between the two alloys.

This study examines the spatial variability of HV5 hardness in industrially produced Direct Chill (DC) cast EN AW-5083 aluminium alloy ingots in the as-cast and homogenized conditions. Hardness measurements were performed at predefined sampling positions in the front and rear sections of six ingots using a Latin square design and evaluated by analysis of variance (ANOVA), coefficients of variation, correlation analysis, and linear regression. The results indicate a uniform longitudinal hardness distribution, with similar mean HV5 values at the front and rear sections, while significantly larger variations occur across the ingot cross-section. Slice height (i) and slice width (j) were identified as the dominant sources of variability. Homogenization reduced the overall mean HV5 from 81.8 HV5 to 75.7 HV5, decreased the coefficient of variation from 5.56% to 4.64%, and increased the correlation coefficient from r = 0.76 to r = 0.85. A statistically significant but limited relationship between the number of grains per unit area (NA) and hardness was observed, indicating that NA contributes to local hardness variations but is not the dominant factor controlling the overall spatial hardness distribution. The results indicate that homogenization does not increase hardness but improves its spatial homogeneity primarily through reduction of local microstructural and compositional heterogeneity.