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In this work, the casting process under mechanical agitation in the semi-solid state was investigated for the production of ZK60 magnesium alloy modified with the addition of 2.5% wt ofmischmetal. The results show that this process enables the production of ingots with homogeneous chemical composition and free of shrinkage, inner defects and internal oxidation. The as-cast microstructure consists of an α-Mg matrix with globular grains reinforced by a grid of distinct intermetallics of Mg-Zn, Mg-Zn-RE and Mg-RE type along the grain boundaries. The yield strength at room temperature undergoes more than 50% increase during direct T5 aging, thus reaching 170 MPa. At 300°C, however, the dispersion of nanometric precipitates does not modify the hot deformation behavior of the aged alloy, which undergoes dynamic recrystallization in a similar manner to the as-cast alloy. DRX at 300°C is fastest for the alloy solution-treated at 500°C.

Bergenin may represent a novel alternative antioxidant, with potential applications in various industries, including drugs, cosmetics, and foods.

Rare earth elements reportedly improve high temperature strength and creep resistance of Mg alloys. In the present work, ZK60 Mg alloys containing different amounts (0.5, 1.5 and 2.5 wt.%) of rare earth additions were prepared by thixocasting and submitted to solution and ageing heat treatments (T4, T5 and T6). The as-cast and heat treated microstructures were investigated by scanning electron microscopy and hardness was evaluated as a function of heat treatment parameters. In the as-cast state, the alloys are formed by globular α-Mg grains reinforced by a network of composite Mg-Zn-RE precipitates with either smooth or lamellar/acicular morphologies. Solution of the smooth precipitates took place in alloys containing 0.5 and 1.5wt.%RE for T4-500 °C but no precipitates were dissolved with T4-380 °C. The optimum temperature for T5 and T6 was identified as 175 °C, while T6-500 °C led to the highest hardness, followed by T5 and T6-380 °C, respectively.

Collagen is considered the most abundant protein in the animal kingdom, comprising 30% of the total amount of proteins and 6% of the human body by weight. Studies that examine the interaction between silver nanoparticles and proteins have been highlighted in the literature in order to understand the stability of the nanoparticle system, the effects observed in biological systems, and the appearance of new chemical pharmaceutical products. The objective of this study was to analyze the behavior of silver nanoparticles stabilized with collagen (AgNPcol) and to check the skin permeation capacity and action in paw edema induced by carrageenan. AgNPcol synthesis was carried out using solutions of reducing agent sodium borohydride (NaBH), silver nitrate (AgNO) and collagen. Characterization was done by using dynamic light scattering (DLS) and X-ray diffraction (XRD) and AFM. Cellular viability testing was performed by using flow cytometry in human melanoma cancer (MV3) and murine fibroblast (L929) cells. The skin permeation study was conducted using a Franz diffusion cell, and the efficiency of AgNPcol against the formation of paw edema in mice was evaluated. The hydrodynamic diameter and zeta potential of AgNPcol were 140.7±7.8nm and 20.1±0.7mV, respectively. AgNPcol failed to induce early apoptosis, late apoptosis, and necrosis in L929 cells; however, it exhibited enhanced toxicity in cancer cells (MV3) compared to normal cells (L929). AgNPcol demonstrated increased toxicological effects in cancer MV3 cells, promoting skin permeation, and preventing paw edema.

In this work, we report on the friction stir weldability of a semi-solid cast ZK60 alloy modified with 1.5 wt% mischmetall in the lap-joint configuration using a 120WV4 steel tool with concave shoulder and conical pin. The coarser solidification microstructure in the semi-solid cast ZK60-1.5%RE alloy requires low strain rates and increased heat input to produce lap-joints without inner defects. This was achieved with 250 rpm tool rotation and 50 mm/min welding speed. Friction stir welding results in a very fine grained microstructure in the stir zone probably due to dynamic recrystallization. In the thermomechanically affected zones dynamic recrystallization seems to occur within the solute enriched intergranular zones. The distribution of longitudinal residual stresses exhibit stress maxima at both thermomechanically affected zones. A compression peak is observed at the retreating side, whereas a tensile stress maximum occurs at the advancing side.

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