Zn In Solution Research Articles

Effects of Zn Addition on the Microstructure, Tensile Properties and Formability of As-Extruded Mg-1Sn-0.5Ca Alloy

In the present study, the influence of the Zn content (0.0, 0.5, 1.0, and 2.0 wt.%) on the microstructure, texture, tensile mechanical properties and formability of Mg-1.0Sn-0.5Ca-based alloys after extrusion were investigated via extrusion of Mg sheets and analysis of the extruded materials. Adding Zn improved the microstructure uniformity and accelerated the formation of more CaMgSn and the Ca2Mg6Zn3 phase. In addition, after the addition of Zn, the texture evolved from the initial extrusion direction tilted bimodal texture to a weakened and symmetrical texture. Compared with the Mg-1.0Sn-0.5Ca alloy, the average tensile yield strength and elongation values were simultaneously improved after 0.5 wt.% Zn addition due to the synergistic effect of the solid solution of elemental Zn, the decreased amount of coarse unrecrystallized grains, and the existence of an additional tilted direction texture component. The formability first increased and then decreased with increasing Zn content. In contrast, the deterioration of formability after the further addition of Zn was closely associated with the increased volume fractions of the coarse CaMgSn and Ca2Mg6Zn3 phases.

A New Family of Macrocyclic Polyamino Biphenolic Ligands: Acid-Base Study, Zn(II) Coordination and Glyphosate/AMPA Binding

In this study, the ligands 23,24-dihydroxy-3,6,9,12-tetraazatricyclo[17.3.1.1(14,18)]eicosatetra-1(23),14,16,18(24),19,21-hexaene, L1, and 26,27-dihidroxy-3,6,9,12,15-pentaazatricyclo[20.3.1.1(17,21)]eicosaepta-1(26),17,19,21(27),22,24-hexaene, L2, were synthesized: they represent a new class of molecules containing a biphenol unit inserted into a macrocyclic polyamine fragment. The previously synthesized L2 is obtained herein with a more advantageous procedure. The acid-base and Zn(II)-binding properties of L1 and L2 were investigated through potentiometric, UV-Vis, and fluorescence studies, revealing their possible use as chemosensors of H+ and Zn(II). The new peculiar design of L1 and L2 afforded the formation in an aqueous solution of stable Zn(II) mono (LogK 12.14 and 12.98 for L1 and L2, respectively) and dinuclear (LogK 10.16 for L2) complexes, which can be in turn exploited as metallo-receptors for the binding of external guests, such as the popular herbicide glyphosate (N-(phosphonomethyl)glycine, PMG) and its primary metabolite, the aminomethylphosphonic acid (AMPA). Potentiometric studies revealed that PMG forms more stable complexes than AMPA with both L1- and L2-Zn(II) complexes, moreover PMG showed higher affinity for L2 than for L1. Fluorescence studies showed instead that the L1-Zn(II) complex could signal the presence of AMPA through a partial quenching of the fluorescence emission. These studies unveiled therefore the utility of polyamino-phenolic ligands in the design of promising metallo-receptors for elusive environmental targets.

Structural, optical, photoluminescence, and magnetic properties of Mo0.6−xTi0.3Zn0.1ErxO3 nanorods films fabricated by sol–gel/spin coating technique

Er3+-incorporated Mo0.6−xTi0.3Zn0.1 nanorods thin films were prepared on glass substrates via controlled sol–gel method. The Mo, Zn, Ti, and Er solutions were prepared using ammonium dimolybdate, titanium isopropoxide, zinc acetate dehydrate, and erbium nitrate as the starting material. Ethylene glycol, monoethanolamine, and HCl acid are solvents and solution stabilizers in the sol–gel process. The effect of the Er3+ concentration (0 ≤ x ≤ 0.3 mol%) on the films structure, optical, photoluminescence, and magnetic properties of the nanorods films was investigated by XRD, SEM, Pl, and magnetic measurement. XRD analysis proved that the samples with Er doping = 0.0 and 0.1 consists of single-phase MoO3. By increasing erbium doping to 0.2 and 0.3, bi-phasic were obtained, one of them MoO3 and the other was related to Ti6O11. These results indicate that MoO3 (two-dimensional) can control the internal growth of the Mo0.6−xTi0.3Zn0.1ErxO3 film's structure as supported by SEM and FTIR results. The reflectance of doped films exhibits high values that are increasing with the Er ratio, which adapted an increase in the Eg values from 2.85 to 3.25 eV. The presence of Er3+ in the films is found to sense the photoluminescence process that reveals two emission lines at 1477 and 1543 nm for Er ions. Magnetization behavior for samples exhibits antiferromagnetic behavior with weak ferromagnetic and unsaturated characteristics, where the magnetization at the maximum field (Mmax) increases with increase in Er content.

SYNTHESIS AND CHARACTERIZATION OF TRANSPARENT PHOTOCATALYTIC ZTO COATINGS

The photocatalytic approach is known to be one of the most promising processes for the tertiary treatment of polluted water. The paper presents studies of Zn2SnO4 (ZTO) coatings synthesized by spray pyrolysis of Zn and Sn salt solution with the addition of dispersed Ta2O5 powder. The structural, morphological and optical properties of the coatings were investigated. Despite the simplicity and availability, the spray pyrolysis method provides homogeneous coatings. Introducing 0.001 mol/L of Ta2O5 into the initial salt solution was found to contribute to a significant change in the surface morphology of the synthesized coatings. The effect of the doped Ta2O5 phase on the photocatalytic activity of ZTO for the degradation of methylene blue (MB) has been investigated. An improvement of up to 90% in the degradation of MB has been observed for the Zn2SnO4/Ta 2O5 system after five hours of UV irradiation.

Homogenization treatment of Mg-6Zn-3Sn (wt.%) alloy and its effects on microstructure and mechanical properties

With DSC, OM, XRD, SEM, TEM, Vickers hardness tester, and universal testing machine, the evolution of the microstructure and mechanical properties of Mg−6Zn−3Sn alloy during homogenization was studied, the reason for overburning and diffusion kinetics of the alloy were analyzed, and the homogenization scheme was determined. The results show that the decomposition of the Mg2Zn3 phase, accompanied by the precipitation of the Mg2Sn phase, occurs after the single-stage homogenization. When the homogenization temperature increases to 350 °C, the Mg2Zn3 phase leads to overburning. The suitable homogenization scheme for the alloy is (335 °C, 24 h) + (400 °C, 6 h). During the double-stage homogenization, the hardness of the alloy decreases continuously and the mechanical properties show an increase first and then decrease, which is related to the solid solution of Zn and Sn atoms and the precipitation of the Mg2Sn phase.

Synthesis, characterization and adsorptive performance of CuMgAl-layered double hydroxides/montmorillonite nanocomposite for the removal of Zn(II) ions

Developing an effective adsorbent for removing heavy metals is an interesting field in water and wastewater treatment research. This work successfully prepared and used a CuMgAl-layered double hydroxide/montmorillonite nanocomposite (CuMgAl-LDH/MMt) for the adsorption of heavy metal pollutants from an aqueous solution. The nanocomposite had a maximum adsorption capacity of 154.21 mg/g for Zn(II) ion adsorption. The Langmuir model and pseudo-second-order kinetic model presented a better fit for the Zn(II) adsorption process. The mechanism of Zn(II) adsorption mainly involves exothermic and spontaneous processes. Moreover, the effects of solution pH, pollutant concentration, adsorbent dose, temperature, and repeated use of CuMgAl-LDH/MMt on the Zn(II) adsorption were tested, revealing that CuMgAl-LDH/MMt has excellent stability and the ability to remove Zn(II) The maximum removal rate (95.1 %) was determined under conditions of pH = 5, CuMgAl-LDH/MMt dosage = 0.25 g per100 ml Zn(II) solution, particle size of adsorbent = 87 µm, shaking speed = 200 rpm, temperature = 25 °C, initial concentration = 70 mg/L, and adsorption time = 90 min. In conclusion, this study demonstrates the value of CuMgAl-LDH/MMt as the best adsorbent for the removal of Zn(II) ions from wastewater compared to other adsorbents used for the same purpose.

A New Concept for Adsorption Studies Using a Brush-Type Adsorbent (Magnetite Coated Animal Fibers)

ABSTRACT The brush-type adsorbent is an innovative material that provides significant advantages to adsorption processes and contains effective and diversifiable materials such as nanomaterials. The adsorbent can be separated from the environment by a single movement and it brings practicality, convenience, and low-cost to batch and column systems. The brush fibers were successfully coated with the adsorptive materials obtained from Fe(II)/Fe(III), Ag(I), Cu(II), Zn(II), and Ni(II) solutions. The particle size of magnetite nanoparticles formed on brush fibers is about 60 nm. SEM-EDX analysis showed that uncoated brush fibers mainly contained carbon, oxygen, and sulfur. Also, magnetite nanoparticles are spherical and contain iron and oxygen. The adsorbents have high removal efficiencies (80–94%) for arsenic, cadmium, lead, molybdenum, selenium, and thallium. The pseudo first-order, the pseudo second-order, Elovich, and the intraparticle diffusion kinetic models were fitted to the experimental data. The pseudo-second-order mechanism was predominant (R2 = 0.99–1.00) for all the elements, and the adsorptions are chemical in nature. The adsorbent can be produced for various purposes, in different contents and sizes. The use of this brush-type adsorbent for water and air pollutants will contribute to both the environment and the economy by facilitating and reducing the adsorption stages.

Dislocation characteristics and dynamic recrystallization in hot deformed AM30 and AZ31 alloys

Zn addition to Mg alloys activates non-basal slip or twinning with solute softening effects. On the other hand, the effects of the Zn solute on the macroscopic dislocation behavior and dynamic recrystallization are not completely understood. Moreover, it is unclear if <c+a> slip can be affected by changes in the c/a ratio of solute atoms. This study was conducted to understand the solute strengthening of Zn addition and its effects on the dislocation characteristics and dynamic recrystallization. A hot torsion test was performed on both AM30 and AZ31 alloys up to a high strain to investigate the Zn solute effect on the dislocation characteristics and dynamic recrystallization. The dislocation components of the hot torsioned alloys were evaluated by X-ray line profile analysis and electron backscatter diffraction. The results showed that the Zn solutes slightly accelerate strain accumulation at the initial stages of hot deformation, which accelerated recrystallization at high strain. The dislocation characteristics were changed dynamically by Zn addition: fortified <c+a>-type slip, dislocation arrangement and strain anisotropy parameters. The most important point was that the dislocation characteristics were changed dramatically at the critical strain for recrystallization and high strain regions. The addition of Zn also acted greatly in these strain areas. This indicates that the rapid formation of <c+a>-type slip at the serrated grain boundaries occurs at the initiation of dynamic recrystallization and the increase in the grain triple junction because grain refinement has a great influence on the dislocation characteristics at high strain.

Activation of second-order pyramidal slip and other secondary mechanisms in solid solution Mg-Zn alloys and their effect on tensile ductility

This work investigates the strain-dependent activation of second-order <c+a> pyramidal slip and other non-basal systems with increasing tensile strain in a Mg-Zn alloy. With that purpose, a polycrystalline solid solution Mg-Zn alloy with ∼2 wt.% Zn (∼0.75 at. %) and with an average grain size of ∼36 μm was processed by casting, hot rolling and subsequent annealing. The slip activity with tensile strain was analyzed by electron backscattered diffraction (EBSD)-assisted slip trace analysis. Basal slip was found to be the dominant deformation mechanism at low strains (∼5-10%). However, at higher strains the activity of pyramidal slip increases significantly due to the hardening of basal slip by Zn solutes. Other non-basal deformation mechanisms, such as compression twinning, cross-slip and slip transfer between pyramidal planes, come into play also at higher strains and are shown to be induced by pyramidal slip. Molecular dynamics (MD) simulations have been used, in particular, to demonstrate the influence of pyramidal dislocations on the nucleation of compression twins. The large availability of deformation mechanisms at high strains contributes to improve the RT ductility of the Mg-Zn alloy.

Phytotoxicity level and accumulation ability of pot marigold (Calendula officinalis L.) to zinc

The study aims to reveal the effects of different Zn levels on pot marigold. We determined some germination and young seedling properties in the first experiment, and morphological, stomatal, and physiological parameters besides uptake profiles of both Zn and other plant nutrients in the second one. We supplied the water requirement of the seeds with Zn solutions (0, 250, 500, 750, and 1,000 mg l−1) in the first experiment, and We added the same zinc doses as mg kg−1 to the soil of the pots where the plants would grow in the second one. As a result, the inhibitory effects were more prominent in the early seedling stage (especially at 1,000 mg l−1 Zn) than in the germination one. We determined plant growth retardation, decreases in leaf water contents, and increases in membrane damages with higher Zn (≥500 mg kg−1) in the experiment conducted by potting soil. We detected decreases in chlorophyll parameters parallel with the increases in Zn. The alterations in plant zinc contents revealed the accumulation capacity of pot marigold in potting conditions. That TF value >1 in Zn treatments up to 500 mg kg−1 points to the efficiency limit of pot marigold as a Zn-accumulator plant.

Significant enhancement in tensile strength of room-temperature rolled Al–8Zn–1Mg alloy induced by profuse microbands

Developing high-performance simpler alloys via simpler processing procedures is of great significance in achieving carbon dioxide emission peak and carbon neutrality. In the present study, room-temperature (RT) rolling was carried out on simple ternary Al–8Zn–1Mg alloy in order to improve its comprehensive performance by regulating microstructure evolution. Ultimate tensile strength (UTS), yield strength (YS), fracture elongation (EL%) and uniform elongation (EU%) were tested. Optical microscopy (OM), electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were used to characterize the microstructure evolution. Phase analysis was performed by X-ray diffraction (XRD). The results show that RT rolling significantly enhances the UTS and YS of ternary Al–8Zn–1Mg alloy, which are ∼447 MPa and ∼389 MPa, respectively, with the corresponding EL% and EU% of ∼7.1% and ∼4.1%. The comprehensive tensile properties are comparable to or even better than that of their conventional counterparts with more complex compositions or produced by more complicated techniques. Compared with the as-SS alloy, the as-SS + R alloy experiences an additional 227 MPa increase in YS. The calculated results show that fine-grain strengthening and dislocation strengthening (predominantly in the form of microbands in the present study) respectively contribute to 21 MPa and 167 MPa increases in YS. The remaining 40 MPa increase is highly likely derived from the hetero-deformation induced (HDI) strengthening of the heterostructured lamellar microbands. The delicate balance between strength and elongation is mainly attributed to the profuse microbands formed by the coupling effect of high Zn solute atoms and stress. The findings shed light on a fundamental facet of how regulating microbands can develop high performance simpler aluminum alloys which have potential applications in strength-based structural materials.

Agro-Industrial Waste as Potential Heavy Metal Adsorbents and Subsequent Safe Disposal of Spent Adsorbents

Water pollution is an environmental problem that affects the ecosystem and living beings. Adsorption is one of the best technologies for the removal of heavy metals. Since waste recovery is the basis of the Circular Economy, agro-industrial waste is emerging as low-cost adsorbents for these pollutants from wastewater. Residues of pine sawdust, sunflower seed hulls and corn residues mix were evaluated as adsorbents of synthetic aqueous solutions of Ni(II), Zn(II) and Cd(II). These residues were characterized to determine their structure and composition, and to understand the adsorption mechanism. Adsorption efficiencies and capacities for the adsorbents and adsorbates were determined and compared. From the obtained results, it is possible to affirm that all biomasses used are good alternatives to the synthetic materials, with adsorption efficiencies greater than 50%. The order of adsorption was Cd &gt; Zn &gt; Ni. At the concentration range checked, adsorption efficiencies decreased in sawdust when a mixture of all metals together was considered (as present in real sewage). Finally, the heavy metals were immobilized, with efficiencies over 88.5%, in clay ceramics (as brick’s precursors). This procedure would help to minimize the contamination that could be generated by the disposal of spent adsorbents, rarely explored in the literature.

Fabrication of transparent ZnO/Cu-Mg(OH)2 heterojunction diodes by electrochemical deposition

The pn heterojunction diodes were fabricated using p-type Cu-doped Mg(OH)2 and n-type ZnO. The Cu-Mg(OH)2 thin films were fabricated via electrochemical deposition (ECD) using an aqueous solution of Mg(NO3)2 and Cu(NO3)2. The ZnO films were deposited on the Cu-Mg(OH)2 film via ECD from a solution of Zn(NO3)2. The Cu-Mg(OH)2 films were transparent in the visible range and showed a clear p-type response during photoelectrochemical measurement. The ZnO/Cu-Mg(OH)2 diodes exhibited appreciable rectification properties. Thus, Mg(OH)2 can be a promising ultra-wide bandgap semiconductor for transparent electronics applications.

(Digital Presentation) The Role of Iron in the Zinc Electrodeposition from Chloride Media for Recovering Zinc from Spent Pickling Liquors

Electrodeposition of Zn from chloride media had been studied by potentiodynamic method to understand the characteristics of Zn recovery from spent pickling liquor (SPL). Various concentration, pH, agitation speed and impurities contamination were examined in the series of experiments. The influence of Zn concentration in the range of 30-150 g/dm3 relevant to the real SPL were studied along with acidity level change (pH 1.5-5.5). It was found that the cathodic deposition started with the uniform patern followed by sponge-like deposit and as the concentration of the electrolyte near the cathode surface decreased, the dendritic deposition start to grow, especially at the edge of the cathodes.It was found that the effect of iron concentration on the polarization curves of zinc from SPL is complex. Initially it has a negative effect on the generated cathodic current because of the enhancement of hydrogen bubble formation. At a higher concentration range, however, iron deposits at a relatively higher rate. Further increased iron concentrations may make the composition of the Zn-Fe deposit dominantly in favor of iron, resulting in a hydrogen dominated cathodic mechanism. It is also characterised by the loss of the dendritic structure – attributed mostly of zinc deposition when hydrogen bubbles are not blocking the cathode. As the gas evolution becomes more characteristic, the deposit tends to become more powdery. Under such conditions the cathode becomes smoother and the active surface is reduced. Increasing the stirring speed, the powder was easily detached from the cathode surface. Iron, however can enhance the cathodic deposition process of zinc. With 30 – 60 g/dm3 iron in the 90 g/dm3 Zn solution, an increased iron concentration resulted in a significant increase in the mass of the deposited zinc. This may be interpreted by a beneficial effect of the increased hydrogen evolution enhancing the zinc ion transport to the electrode surface. However further increments of iron had a contrary effect, possibly by the locally increased – and generally detected – pH of the solution indirectly causing a superficial precipitation of hydroxides. Technically pure zinc could be deposited from only low-iron (< < 30 g/dm3) zinc solutions (of 90 g/dm3 Zn) at relatively vigorous stirring speeds. High iron concentration in the solution is definitely unsuitable for obtaining the aimed quality of cathode zinc.

Extraction of Heavy Metals from Aqueous Solutions of Zn,Al- and Mg,Al-Layered Double Hydroxides Intercalated with Citrate and EDTA Ions and Their Composites with Magnetite

Extraction of Heavy Metals from Aqueous Solutions of Zn,Al- and Mg,Al-Layered Double Hydroxides Intercalated with Citrate and EDTA Ions and Their Composites with Magnetite

Molecular platform based on a spiroindolinonaphthopyran of the diphenyloxazole series for the creation of polychromogenic molecular systems

A spiroindolinonaphthopyran of the diphenyloxazole series along with photochromism possesses a number of chromogenic properties such as solvatochromism, ionochromism, solid state phasochromism and fluorescence. The nature of these effects is associated both with the possibility of the spiropyran existence under its two forms (cyclic and merocyanine) and with the peculiarities of the molecular structure, in particular, with the presence of a diphenyloxazole fragment. Photochromic properties of the spiroindolinonaphthopyran do not exhibit a drastic dependence on the nature of solvents, including those that are capable of specific intermolecular hydrogen bond interactions. In addition, good resistance to photodegradation in the mode of photochromic balance opens up possibilities for designing polychromogenic molecular systems based on them. The positive solvatochromism of the first type, which is noticeably manifested in the case of merocyanine isomers, allowed establishing the weak polarity of their ground state. Solvatochromism of the second type demonstrates a significant spectral contrast (up to 227 nm) due to the existence of an equilibrium of cyclic and merocyanine isomers. The intensity of the effect increases upon passing from toluene to DMSO due to the shift of the equilibrium towards the merocyanine isomers. The presence of a chelate center formed by the merocyanine oxygen atom and the nitrogen atom of the diphenyloxazole fragment allows observing ionochromic transformations of the spiropyran molecule associated with the formation of coloured complex compounds upon its interaction with Co, Cu, Ni, Zn, Cd, Mn ions. It has been established that solutions of Zn, Cd, and Mn complexes exhibit the negative photochromism properties. The change in the solid state of spirpyran is accompanied by a change in the ability to undergo photochromic transformations. Under standard conditions the spiropyran exhibits photochromic properties in the crystalline state, but not in the amorphous one. The combination of chromogenic properties makes it possible to implement fluorescent molecular switches, bipolar absorption switches, photodynamic chemosensors, and solid-state phase transitions control the chromogenic properties based on spiropyrans of diphenyloxazole series. The possibility of structural modification leading to an enhancement of some properties and/or a weakening of other ones makes it possible to consider a spiroindolinonaphthopyran of a diphenyloxazole series as a molecular platform for creating polychromogenic molecular systems with desired properties.

Pumpkin Skin Polysaccharide-Zn(II) Complex: Preparation, Characterization, and Suppression of Inflammation in Zebrafish.

In this study, pumpkin (Cucurbita moschata) skin polysaccharide–zinc(II) (PSP−Zn) complex was successfully prepared. The structure and physicochemical properties of PSP and PSP−Zn were analyzed. The anti-inflammatory activity of PSP and PSP−Zn was investigated in zebrafish larvae induced by copper sulphate. PSP and PSP−Zn consisted of rhamnose, arabinose, galactose, glucose, and galacturonic acid. The molecular weight (Mw) of PSP and PSP−Zn were 3.034 × 106 and 3.222 × 106 Da, respectively. Fourier transform infrared spectrum (FT-IR) and circular dichroism (CD) analysis results suggested that the chemical modification of zinc might occur through hydroxyl groups of PSP. The PSP−Zn complex had lamellar texture, smooth surface morphology, and larger particle size. X-ray Diffraction (XRD) analysis revealed that both PSP and PSP−Zn were semi-crystalline substances. PSP−Zn solution showed superior stability in a weak acid and alkaline environment, especially at pH = 6.0. Moreover, PSP and PSP−Zn showed a good inhibitory effect on inflammation cells in zebrafish. Real-time quantitative polymerase chain reaction (RT-PCR) result suggested that the anti-inflammatory mechanism of PSP and PSP−Zn were through downregulation of the expression of nitric oxide synthase 2b (nos2b), inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and nuclear factor-kappa B2 (NF-κB2). The present study indicated that PSP−Zn is expected to be a safe and efficient novel zinc supplement with anti-inflammatory activity.

Electroless Deposits of ZnO and Hybrid ZnO/Ag Nanoparticles on Mg-Ca0.3 Alloy Surface: Multiscale Characterization

ZnO and hybrid of ZnO/Ag structures in the nanometer size were electroless deposited on the Mg-Ca0.3 alloy surface, achieved from aqueous solutions (10−3 M at 21 °C) of ZnO (suspension), Zn(NO3)2 and AgNO3. The surface characterization of the deposits was carried out by Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), X-Ray Photoelectron Spectroscopy (XPS), Fourier transform infrared (FTIR), UV-Visible and Raman spectroscopy. The nanoparticles (NPs) area size distribution analysis revealed that the average of ZnO-NPs was ~85 nm. Likewise, the Ag-NPs of electroless deposits had an average area size of ~100 nm and nucleated in the vicinity of ZnO-NPs as Ag+ ions have been attracted by the negatively charged O2− atoms of the Zn-O dipole. The ZnO-NPs had the wurtzite structure, as indicated by Raman spectroscopy analysis and XRD complementary analysis. The UV-Visible spectroscopy analysis gave a peak at ~320 nm associated with the decrease in the imaginary part (k) of the refractive index of Ag-NPs. On the Mg-Ca0.3 surface, MgO, Mg(OH)2 and MgCO3 are present due to the Mg-matrix. XRD spectra of Ag-NPs indicated the presence of planes arranged with the FCC hexagonal structure. The reported hybrid ZnO/Ag electroless deposits of NPs are of interest for temporary implant devices, providing antibacterial properties to Mg-Ca0.3 surface, a widely used biodegradable material.

Deformation induced solute segregation and G.P. zone formation in Mg-Al and Mg-Zn binary alloys

A dispersion of Guinier Preston (G.P.) zones yields attractive mechanical properties in wrought magnesium alloys. However, the precipitation of G.P. zones has been reported in a limited number of Mg alloys. Here, we report deformation-induced G.P. zone precipitation in Mg-9Al and Mg-5 Zn (wt.%) alloys following equal channel angular extrusion at 150 °C. While the extrusion leads to the formation of a bimodal grain structure consisting of unrecrystallized and recrystallized regions, atom probe tomography reveals a high number density of G.P. zones across both regions. Furthermore, hybrid molecular dynamics/Monte Carlo simulations suggest that the attraction of Al and Zn solute atoms to vacancy clusters formed from excess vacancies during extrusion could be the major driving force for the G.P. zone formation. This combination of experiments and computations demonstrates that strategic control of atomic-scale defects can generate novel, far from equilibrium, microstructures, thereby providing an innovative approach to strengthening severely deformed Mg alloys.

Enhanced softening resistance and mechanical properties of Cu-Ni-Sn alloy with Al, Zn and Si micro-alloying

Microalloying is an effective method for enhancing the mechanical properties and softening resistance of alloys. The effects of microalloying with Al, Zn, and Si on the microstructure, physical properties, and softening resistance of Cu-Ni-Sn alloy were investigated. The results showed that the micro-alloying of Al, Zn, and Si suppressed the segregation of the Cu-Ni-Sn alloy. After 70% cold rolling and 400 °C aging, the Cu-15Ni-5.5Sn-1.5Al-0.5Zn-0.5Si alloy reaches its maximum hardness of 418 HV, which is 16 HV and 38 HV higher than that of Cu-15Ni-8Sn and Cu-15Ni-5.5Sn alloys, respectively. Furthermore, Al, Zn, and Si microalloying can increase the softening temperature of Cu-Ni-Sn alloy. Cu-15Ni-5.5Sn-1.5Al-0.5Zn-0.5Si alloy's softening temperature was 560 °C, which was higher than Cu-15Ni-8Sn (400 °C) and Cu-15Ni-5.5Sn (420 °C) alloys. The softening of the alloy is mainly caused by the rapid formation of discontinuous precipitates and the reduction of dislocation density. The Al and Zn solute atoms dissolved in the matrix and the micron-scale Ni31Si12 phase forms can effectively inhibit discontinuous precipitation formation and dislocation movement during the aging and annealing process, resulting in excellent mechanical properties and softening resistance of the Cu-15Ni-5.5Sn-1.5Al-0.5Zn-0.5Si alloy. In further works, continued efforts are needed in the multi-component design of Cu-Ni-Sn-x alloy to optimize its comprehensive performance.