Antimicrobial resistance (AMR) is one of the most significant global health threats of the 21st century, driving the urgent search for alternatives to conventional antibiotics. Copper nanoparticles (CuNPs) have gained attention due to their broad antimicrobial spectrum, cost-effectiveness, and versatile applications in medicine, agriculture, and the food industry. This review provides a systematic overview of the advances in CuNP synthesis, mechanisms of antimicrobial action, biomedical and industrial applications, and associated toxicity issues. A comprehensive literature review was conducted, covering chemical, physical, and biological synthesis strategies; mechanistic studies on microbial inhibition; and experimental reports on biomedical and environmental applications. A comparative analysis revealed opportunities, limitations, and knowledge gaps, with particular emphasis on cytotoxic and ecotoxicological aspects. CuNPs show strong antimicrobial activity against bacteria, fungi, viruses, and multidrug-resistant strains through mechanisms such as reactive oxygen species (ROS) generation, membrane disruption, and DNA/protein interactions. Their use in medical devices, wound dressings, textiles, and packaging materials underlines their application potential. However, cytotoxicity to mammalian cells, ecological risks, and the lack of standardized safety protocols remain critical challenges. Particle size, morphology, and surface chemistry strongly influence both efficacy and toxicity, underlining the importance of controlled synthesis and functionalization. Overall, CuNPs represent a promising strategy to tackle the AMR crisis. Future research should focus on environmentally friendly and surface-modified synthesis approaches, standardized toxicity assessments, and robust regulatory frameworks. By balancing antimicrobial efficacy with biosafety and sustainability, CuNPs could become a transformative platform for clinical, industrial, and environmental applications.

Aluminum bronze is a complex group of copper-based alloys that may include up to 14% aluminum, but lower amounts of nickel and iron are also added, as they differently affect alloy characteristics such as strength, ductility, and corrosion resistance. The phase transformations of nickel aluminum–bronze alloys have been the subject of many studies due to the formations of intermetallics promoted by slow cooling. In the present investigation, quaternary systems of aluminum bronze alloys, specifically Cu–10wt%Al–5wt%Ni–5wt%Fe (hypoeutectoid bronze) and Cu–14wt%Al–5wt%Ni–5wi%Fe (hypereutectoid bronze), were directionally solidified upward under transient heat flow conditions. The experimental parameters measured included solidification thermal parameters such as the tip growth rate (V_L) and cooling rate (T_R), optical microscopy, scanning electron microscopy (SEM) analysis, hardness, and microhardness. We observed that the hardness and microhardness values vary according to the thermal parameters and solidification. We also observed that the Cu–14wt%Al–5wt%Ni–5wi%Fe alloy presented higher hardness values and a more refined structure than the Cu–10wt%Al–5wt%Ni–5wt%Fe alloy. SEM analysis proved the presence of specific intermetallics for each alloy.

Copper and its alloys are structural materials used in industries and engineering applications due to their excellent thermal and electrical conductivity and chemical stability. Integrating graphene, known for its exceptional electrical conductivity, into the copper matrix is a promising strategy to enhance mechanical properties without sacrificing electrical conductivity. The Accumulative Roll Bonding (ARB) process can effectively and homogeneously introduce graphene into the metal matrix and is adaptable to an industrial scale. This study investigates the impact of varying graphene concentrations and two heat treatment protocols (without a controlled atmosphere) on the mechanical and electrical properties of ARBed copper/graphene composites. Optical microscopy revealed minimal voids and graphene clumps, and the energy dispersive spectroscopy analysis revealed the absence of copper oxide in some samples. The conductivity test showed little influence of the graphene content and stress relief heat treatment temperature on electrical conductivity (~86% of the International Annealed Copper Standard) within a limited number of ARB cycles. The tensile tests did not reveal a significant influence of the graphene content and stress relief heat treatment temperature on the ultimate tensile strength (220–420 MPa) and elongation (~2%).

The Cu-8.5wt % Sn alloy presents an extensive microsegregation during its solidification. That microsegregation results in the formation of a eutectoid mixture, which is detrimental to subsequent forming processes. This study deals with the influence of solidification time and cooling rate on the microstructure of that alloy. The unidirectional solidification technique allowed the acquisition of thermal data. The optical microscopy enabled the microstructural characterization of the material, the measurement of dendrite arm spacings and the quantification of the volume fraction of the eutectoid mixture. A semi-analytical mathematical model was proposed to estimate the volume fraction of the eutectoid mixture. The model expresses the volume fraction as an implicit function of the Fourier number. The results showed that the microstructure is dendritic and that the characteristic spacings increase with the solidification time between theliquidusand the peritectic temperatures. The data also showed that for higher cooling rates the dendrite arm spacings are smaller and that there is a tendency for the volume fraction of eutectoid mixture in the columnar zone to increase with the Fourier number and to decrease with the cooling rate. The proposed model allowed obtaining values of volume fraction with the same order of magnitude of the experimental data, but with behavior tendency opposite to that observed.

This study aims to correlate thermal parameters in the directional solidification of Al-10wt% Si-5wt% Cu alloy with the resulting microstructure and, in addition, with hardness and corrosion resistance. The results include primary dendritic arm spacing (PDAS),tip growth rate(V_L), cooling rate (T_R), scanning electron micrographs (SEM), hardness values and corrosion resistance parameters obtained by electrochemical impedance spectroscopy (EIS) and by the Tafel extrapolation method, conducted in 3% (m/v) NaCl solution at room temperature. The results show that coarser PDAS exhibit a tendency to increase in corrosion resistance, except in the positions with higher concentrations of the intermetallic compound Al₂Cu, that surrounded by an aluminum rich phase tends to have a higher resistance to corrosion. The hardness values remained constant.