Zn Alloy Research Articles

Alloying strategy to stabilize monocrystalline zinc anode under high utilization and working capacity

Zn(002) has been proven as a dendrite-free anode for Zn batteries. However, stable Zn plating/stripping behavior at an areal capacity exceeding 5 mAh cm−2 has remained unfulfilled so far. In this study, we show that the planar deposit on pure Zn (002) substrate is loosely stacked with high corrosion tendency by the aqueous electrolyte, the key obstacle to achieving considerable efficiency under high-capacity working conditions. To mitigate the side reactions, we introduce an alloying approach by combining monocrystalline Zn(002) with eutectic Al and Cu. The alloying strategy enhances the electrostatic interaction between deposits and substrate, favoring a dense-packed deposition morphology with improved corrosion resistant ability. Solid solution property of Al and Cu in Zn matrix also ensures the structure stability during repeated plating/stripping cycles. As a result, significant extension in cycle life of Zn alloy (002)-based symmetric cells even under 50 mA cm−2 and 25 mAh cm−2 and performance with high utilization also achieves a leading level without extra methods on surface protection. The modified Zn alloy (002) anode induces high anode utilization, paving the way for Zn batteries to meet the requirements of practical applications.

Revealing the Influence of Electron Migration Inside Polymer Electrolyte on Li+ Transport and Interphase Reconfiguration for Li Metal Batteries

AbstractThe development of highly producible and interfacial compatible in situ polymerized electrolytes for solid‐state lithium metal batteries (SSLMBs) have been plagued by insufficient transport kinetics and uncontrollable dendrite propagation. Herein, we seek to explore a rationally designed nanofiber architecture to balance all the criteria of SSLMBs, in which La0.6Sr0.4CoO3−δ (LSC) enriched with high valence‐state Co species and oxygen vacancies is developed as electronically conductive nanofillers embedded within ZnO/Zn3N2‐functionalized polyimide (Zn‐PI) nanofiber framework for the first time, to establish Li+ transport highways for poly vinylene carbonate (PVC) electrolyte and eliminate nonuniform Li deposits. Revealed by characterization and theoretical calculation under electric field, the positive‐negative electrical dipole layer in LSC derived from electron migration between Co and O atoms aids in accelerating Li+ diffusion kinetics through densified electric field around filler particle, featuring a remarkable ionic conductivity of 1.50 mS cm−1 at 25 °C and a high Li+ transference number of 0.91 without the risk of electron leakage. Integrating with the preferential sacrifice of ZnO/Zn3N2 on PI nanofiber upon immediate detection of dendritic Li, which takes part in reconfiguring hierarchical SEI chemistry dominated by LixNy/Li−Zn alloy inner layer and LiF outer layer, SSLMBs are further endowed with prolonged cycling lifespan and exceptional rate capability.

Achieving excellent strength–ductility combination of Al-aided Mg–Gd–Al–Zr–Zn alloys fabricated by cold metal transfer-based wire-arc directed energy deposition via uniform equiaxed grains and multiple precipitates

Limited ductility consistently poses a challenge for high-strength Mg–RE (rare earth) structures prepared by additive manufacturing. Particularly following heat treatment, while the strength of the Mg–RE alloy experiences a substantial increase, there is a noteworthy decrease in its ductility. Herein, a novel Mg–Gd–Al–Zr–Zn thin wall was successfully fabricated by cold metal transfer-based wire-arc directed energy deposition (CMT-WA-DED) and Al alloying. The microstructural evolution and mechanical properties of deposited and heat-treatment alloys were elucidated systematically. By adding Al element, Al2Gd and Al–Zr phases with thermal stability were precipitated in the deposited alloy. During the solidification or heat treatment stage, Al2Gd and Al–Zr phases could pin grain boundaries to restrict grain growth. The as-deposited alloys exhibited fully equiaxed grains at different heights and orientations. Thus, the thin wall exhibited good isotropic performance. After the heat treatment, the grain size only slightly grew and no abnormal grain growth was observed. Various morphologies of β precipitation phases were discovered along grain boundaries and within the grains. Additionally, a high density of β' and β1 phases within the grains and β phases along the grain boundary played pivotal roles in enhancing the mechanical strength of the Mg–Gd–Al–Zr–Zn alloy. The alloys exhibited an excellent combination of strength and ductility with ultimate tensile strength of 340 ± 7 MPa, yield strength of 212 ± 5 MPa, and elongation of 12.7 ± 0.9 %. This work provides theoretical and practical reference value for the Mg–RE structures obtaining an excellent combination of strength and ductility prepared by additive manufacturing.

Feasibility Insights of the Green-Assisted Calcium-Phosphate Coating on Biodegradable Zinc Alloys for Biomedical Application: In Vitro and In Vivo Studies.

In the field of bone tissue engineering, recently developed Zn alloy scaffolds are considered potential candidates for biodegradable implants for bone regeneration and defect reconstruction. However, the clinical success of these alloys is limited due to their insufficient surface bioactivities. Further, the higher concentration of Zn2+ produced during degradation promotes antibacterial activity, but deteriorates osteogenic properties. This study fabricated an Azadirachta indica (neem)-assisted brushite-hydroxyapatite (HAp) coating on the recently developed Zn-2Cu-0.5Mg alloy to tackle the above dilemma. The microstructure, degradation behavior, antibacterial activity, and hemocompatibility, along with in vitro and in vivo cytocompatibility of the coated alloys, are systematically investigated. Microstructural analysis reveals flower-like morphology with uniformly grown flakes for neem-assisted deposition. The neem-assisted deposition significantly improves the adhesion strength from 12.7 to 18.8 MPa, enhancing the mechanical integrity. The potentiodynamic polarization study shows that the neem-assisted deposition decreases the degradation rate, with the lowest degradation rate of 0.027 mm/yr for the ZHN2 sample. In addition, the biomineralization process shows the apatite formation on the deposited coating after 21 days of immersion. In vitro cytotoxicity assay exhibits the maximum cell viability of 117% for neem-assisted coated alloy in 30% extract after 5d and the improved cytocompatibility which is due to the controlled release of Zn2+ ions. Meanwhile, neem-assisted coated alloy increases the ZOI by 32 and 24% for Gram-positive and Gram-negative bacteria, respectively. Acceptable hemolysis (<5%) and anticoagulation parameters demonstrate a promising hemocompatibility of the coated alloy. In vivo implantation illustrates a slight inflammatory response and vascularization after 2 weeks of subcutaneous implantation, and neo-bone formation in the defect areas of the rat femur. Micro-CT and histology studies demonstrate better osseointegration with satisfactory biosafety response for the neem-assisted coated alloy as compared to that without neem-assisted deposition. Hence, this neem-assisted brushite-Hap coating strategy elucidates a new perspective on the surface modification of biodegradable implants for the treatment of bone defects.

Effect of rare earth elements Ce and Yb on the in vitro properties of biodegradable Zn alloys

Biodegradable pure Zn and zinc alloys have received much attention in recent years, but the mechanical properties, corrosion behavior and biocompatibility of the previous reported pure zinc and zinc alloys do not fully meet the clinical requirements. Alloying and deformation technology are widely used in improving the properties of biodegradable pure Zn and zinc alloys. In this work, we have developed two new types of binary zinc alloys with the two rare earth elements (REE) cerium (Ce) and ytterbium (Yb). The effects of Ce and Yb on the microstructure, mechanical properties, corrosion behavior, in vitro biocompatibility of biodegradable Zn-xCe and Zn-xYb (x = 0.1, 0.2, 0.5, 1.0 wt %) were systematically investigated. The ultimate tensile strength, yield strength and elongation of Zn-xCe and Zn-xYb alloys are significantly improved compared with pure Zn. The Zn-xCe and Zn-xYb alloys have superior antibacterial properties The osteoblast MC3T3-E1 cells exhibited excellent cell activity with polygonal or fusiform extension and adhesion cultured in the series of Zn-xCe and Zn-xYb alloys’ extract solutions, indicating the good in vitro biocompatibility of Zn-xCe and Zn-xYb alloys. This work demonstrated that the Zn-xCe and Zn-xYb binary alloys have great potential as new biodegradable metals for future biomedical implants and devices.

Manipulating scanning strategies towards controlled microstructure of laser remelted Mg–3Al–1Zn alloy

Various laser scanning strategies of multitrack products, consisting of a default Raster pattern (R1), a Raster pattern with a changed line order (R2), and a default Zigzag pattern (Z1), with different overlap rates ranged from 0.7 to 0.5, have been conducted to investigate microstructure evolution for Mg–3Al–1Zn alloy. As the overlap rate changes from 0.7 to 0.5, the average grain size decreases and the texture is slightly concentrated, except for R2 pattern. For effect of different scanning pattern, a relatively small average grain size can be obtained using the R1, R2 patterns compared to using the Z1 pattern; a relatively weak texture can be obtained using the R1, Z1 patterns compared to using the R2 pattern. The utilization of Z1 pattern results in a further texture weakening compared to that of the R1 pattern. Microstructure evolution of scanning strategy is mainly determined by low-undercooling-required epitaxial growth along temperature gradient directions at the solid/liquid interface. Combined with computational thermal-fluid dynamics simulation, a strong fluid flow within the molten pool promotes side expansion of the molten pool, resulting in the larger overlap area, the corresponding three-times remelting domain and continuous deflections of grain major axes.

Nano‐engineering in zinc‐based catalysts for CO2 electroreduction: Advances and challenges

AbstractElectrocatalytic CO2 reduction (CO2RR), an emerging sustainable energy technology to convert atmospheric CO2 into value‐added chemicals, has received extensive attention. However, the high thermodynamic stability of CO2 and the competitive hydrogen evolution reaction lead to poor catalytic performances, hardly meeting industrial application demands. Due to abundant reserves and favorable CO selectivity, zinc (Zn)‐based catalysts have been considered one of the most prospective catalysts for CO2‐to‐CO conversion. A series of advanced zinc‐based electrocatalysts, including Zn nanosheets, Zn single atoms, defective ZnO, and metallic Zn alloys, have been widely reported for CO2RR. Despite significant progress, a comprehensive and fundamental summary is still lacking. Herein, this review provides a thorough discussion of effective modulation strategies such as morphology design, doping, defect, heterointerface, alloying, facet, and single‐atom, emphasizing how these methods can influence the electronic structure and adsorption properties of intermediates, as well as the catalytic activity of Zn‐based materials. Moreover, the challenges and opportunities of Zn‐based catalysts for CO2RR are also discussed. This review is expected to promote the broader application of efficient Zn‐based catalysts in electrocatalytic CO2RR, thus contributing to a future of sustainable energy.

Fine tuning the dynamic PdCx formation for enhanced acetylene semi-hydrogenation: The role of gas environment and ZnO addition

Palladium carbide (PdCx) has been extensively reported as active phase in acetylene semi-hydrogenation that can be dynamically formed during reaction. However, fine tuning of dynamic PdCx formation towards enhanced acetylene semi-hydrogenation is of great challenge and the dynamic insights remain elusive. In this paper, the state-of-the-art in situ characterizations have been adopted to elucidate the dynamic PdCx formation for acetylene semi-hydrogenation. The role of hydrogen atmosphere and ZnO addition in tuning the carburization process were clearly identified by in situ spectroscopies. The hydrogen in the gas environment assisted the carbon infiltration via PdHx hydrides, while the addition of ZnO suppress the carburization by the surface Zn alloy. As a result, the carbon content in PdCx can be precisely modulated by altering the hydrogen atmosphere and ZnO additives, and exhibits a linear correlation with the activity of acetylene semi-hydrogenation. The carbon insertion enriched the electron state of Pd sites in PdCx that favors the activation of hydrogen for acetylene semi-hydrogenation. This work thus provides a new route for the design of Pd catalyst for high-performance acetylene semi-hydrogenation by fine tuning the reaction environment and the degree of carburization during dynamic PdCx formation.

Evolution of microstructure and properties of Cu-Cr-Sn-Zr-Zn alloys with different Zn contents

Cu-Cr-Sn-Zr-xZn alloys with different Zn contents (0.087, 0.26, and 0.42 wt%) were prepared by vacuum casting, and the microstructure and properties of these alloys were investigated using different detection methods. The results show that the Zn element could promote the formation of some primary phase Cr particles and parts that were stretched into fibers during cold drawing deformation, thus enhancing the strength of these alloys. Meanwhile, the number of twins in these alloys increases with the increase in Zn content. When Zn content is 0.42%, the Cu0.64Zn0.36 phase is generated, which could play a role in the second phase’s strengthening. The Cu-0.97Cr-0.096Sn-0.068Zr-0.42Zn alloy shows high tensile strength and electrical conductivity properties of 832 MPa and 72%IACS, respectively.

The effect of topological design on the degradation behavior of additively manufactured porous zinc alloy

The advent of additively manufactured biodegradable porous metals presents a transformative opportunity to meet the criteria of ideal bone substitutes. Precisely tailoring their degradation behavior constitutes a pivotal aspect of this endeavor. In this study, we investigated the effects of topological designs on the degradation profile of laser powder bed fusion (LPBF) Zn scaffolds under dynamic in vitro immersion tests. Specifically, four types of Zn-0.4Mn-0.2Mg scaffolds (beam-based: diamond, face center cubic; surface-based: gyroid, schwarz-P) were designed and fabricated. The degradation mechanism of the scaffolds was comprehensively evaluated using both experimental and simulation methods. The results illuminate the profound impact of structural design on the degradation properties of the Zn alloy scaffolds. The beam-based diamond and face center cubic scaffolds exhibited a degradation rate of 0.08–0.12 mm per year with a relatively uniform degradation mode under dynamic immersion. On the contrary, the surface-based gyroid and Schwarz-P scaffolds demonstrated a notably reduced degradation rate due to lower permeability. This restricted the diffusion of medium ions within the pores, culminating in the accumulation of degradation products and more severe localized degradation. This study underscores the potential of topological design as a compelling strategy for tailoring the degradation profile of additively manufactured biodegradable scaffolds, thereby advancing their suitability as bone substitutes.

3D Printing of a Porous Zn-1Mg-0.1Sr Alloy Scaffold: A Study on Mechanical Properties, Degradability, and Biosafety.

In recent years, the use of zinc (Zn) alloys as degradable metal materials has attracted considerable attention in the field of biomedical bone implant materials. This study investigates the fabrication of porous scaffolds using a Zn-1Mg-0.1Sr alloy through a three-dimensional (3D) printing technique, selective laser melting (SLM). The results showed that the porous Zn-1Mg-0.1Sr alloy scaffold featured a microporous structure and exhibited a compressive strength (CS) of 33.71 ± 2.51 MPa, a yield strength (YS) of 27.88 ± 1.58 MPa, and an elastic modulus (E) of 2.3 ± 0.8 GPa. During the immersion experiments, the immersion solution showed a concentration of 2.14 ± 0.82 mg/L for Zn2+ and 0.34 ± 0.14 mg/L for Sr2+, with an average pH of 7.61 ± 0.09. The porous Zn-1Mg-0.1Sr alloy demonstrated a weight loss of 12.82 ± 0.55% and a corrosion degradation rate of 0.36 ± 0.01 mm/year in 14 days. The Cell Counting Kit-8 (CCK-8) assay was used to check the viability of the cells. The results showed that the 10% and 20% extracts significantly increased the activity of osteoblast precursor cells (MC3T3-E1), with a cytotoxicity grade of 0, which indicates safety and non-toxicity. In summary, the porous Zn-1Mg-0.1Sr alloy scaffold exhibits outstanding mechanical properties, an appropriate degradation rate, and favorable biosafety, making it an ideal candidate for degradable metal bone implants.

3D Ternary Alloy Artificial Interphase Toward Ultra‐Stable and Dendrite‐Free Aqueous Zinc Batteries

AbstractRechargeable aqueous zinc‐ion batteries (AZIBs) are one of the most promising post‐lithium battery technologies due to their low cost, high safety, and environmental friendliness. However, their practical development is hindered by the issues of Zn metal anodes, including dendrite growth, passivation, hydrogen evolution and other side reactions. Herein, to circumvent these issues, a facile and universal alloy electrodeposition strategy is proposed to construct a 3D structured ternary Zn alloy artificial interphase layer on Zn foil as an anode for high‐performance AZIBs. The density functional theory (DFT) theoretical calculations, in situ optical visualization and spectroscopic results validate that the zincophilic Zn─Sn─Bi@Zn ternary alloy anode with lower migration energy barrier and weak hydrogen adsorption sites can promote the uniform Zn deposition and suppress hydrogen evolution reactions. The Zn─Sn─Bi@Zn//NH4V4O10 full cell demonstrates a high specific capacity 110.4 mAh g−1 even after 10 000 cycles at 5.0 A g−1. Notably, the full cell with a high NH4V4O10 cathode loading mass of ≈20.0 mg cm−2 maintains cyclic stability for 400 cycles. This work proposes an innovative Zn‐based ternary alloy anode methodology as a design strategy for advanced AZIBs and beyond.

Effect of Zinc and Severe Plastic Deformation on Mechanical Properties of AZ61 Magnesium Alloy.

This study investigates the effects of zinc (4 wt.%) and severe plastic deformation on the mechanical properties of AZ61 magnesium alloy through the stir-casting process. Severe plastic deformation (Equal Channel Angular Pressing (ECAP)) has been performed followed by T4 heat treatment. The microstructural examinations revealed that the addition of 4 wt.% Zn enhances the uniform distribution of β-phase, contributing to a more uniformly corroded surface in corrosive environments. Additionally, dynamic recrystallization (DRX) significantly reduces the grain size of as-cast alloys after undergoing ECAP. The attained mechanical properties demonstrate that after a single ECAP pass, AZ61 + 4 wt.% Zn alloy exhibits the highest yield strength (YS), ultimate compression strength (UCS), and hardness. This research highlights the promising potential of AZ61 + 4 wt.% Zn alloy for enhanced mechanical and corrosion-resistant properties, offering valuable insights for applications in diverse engineering fields.

Effect of Y Contents on the Microstructure, Mechanical Properties, and Corrosion Behavior of Biomedical Mg–0.5Zn Alloy

The effects of Y contents on the microstructure, mechanical properties, and corrosion resistance of biomedical Mg–0.5Zn alloy are investigated. In the results, it is shown that an increase in Y content leads to a growth in the amount of the second phase and a decrease in the spacing of the secondary dendrite arms. Additionally, the second phase changes from a uniformly dispersed point‐like shape to a semicontinuous reticular distribution. Meanwhile, the addition of Y obviously reduces the dendritic organization and this contributes to the improvement of mechanical properties. The corrosion resistance of the alloys increased first when Y content is 2 wt% at most, and then decreases in Mg–3Y–0.5Zn alloy. The gradual improvement of corrosion resistance in Mg–1Y–0.5Zn and Mg–2Y–0.5Zn is closely related to the formation of the compact corrosion layer including Y element, while the sudden drop corrosion resistance of Mg–3Y–0.5Zn alloy is mainly attributed to the presence of a great deal of semicontinuous long‐period stacked order and its excessive negative potential compared with Mg matrix, which leads to a severe pitting.

Investigation of the thermodynamic, structural, electronic, mechanical and phonon properties of D0c Ru-based intermetallic alloys: an ab-initio study

Abstract We present the structural, elastic, electronic, magnetic, and phonon properties of D0c X3Ru (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) alloys in their respective ground-states at zero pressure using first-principles density functional theory (DFT). The calculated heat of formation for Sc3Ru, Ti3Ru, V3Ru, Mn3Ru, and Zn3Ru are negative, signifying their thermodynamic stability. Meanwhile, we find that Sc3Ru, V3Ru, Mn3Ru, Co3Ru, Ni3Ru, Cu3Ru and Zn3Ru alloys are mechanically stable. The electronic properties indicate a metallic nature in all the X3Ru alloys due to valence-conduction band overlap at the Fermi energy. Additionally, the phonon dispersion curves suggest that Cr3Ru, Fe3Ru, Ni3Ru, Cu3Ru, and Zn3Ru are dynamically stable. These results provide a comprehensive overview of the stability, electronic, and mechanical properties of D0c Zn3Ru structures, suggesting their suitability for engineering novel alloys in high-temperature structural applications.

Experimental study of low–cycle fatigue behavior in a Mg–Y–Zn alloy with initial LPSO phase

Asymmetric cyclic stress–controlled low–cycle fatigue (LCF) tests were performed on Mg–Y–Zn alloys with different initial long–period stacking–ordered structure (LPSO) phases at room temperature. The influences of the initial LPSO phase content on the LCF life of the tested alloys were investigated, and an improved Basquin model for predicting the LCF life was proposed, considering the influence of the initial LPSO phase content. The coupling effects of the LPSO phase content and morphology on the LCF behavior were studied through scanning electron microscopy (SEM) experiments on the fatigue fractures of three alloys. The results show that the hindrance degree of LPSO phase to fatigue cracks is affected by the morphology of LPSO phase and the relative position of the LPSO phase with respect to fatigue cracks. When fatigue cracks are perpendicular to the main LPSO phase surface, the hindering effect is more pronounced, and the hindrance degree of the LPSO with different morphologies to fatigue crack propagation predominantly follows this sequence: lamellar > granular > rod > block. When fatigue cracks are relatively parallel to the main LPSO phase surface, the hindrance degree of LPSO relative fatigue cracks with different shapes is mainly in the following order: granular > rod > lamellar > block. The variation of fatigue crack path through the LSPO phase is primarily due to the properties of the LSPO phase itself, followed by morphology and spatial relative position. In addition, under high-stress conditions, fatigue cracks primarily originate from the LPSO phase, whereas under low-stress conditions, fatigue cracks predominantly arise from the matrix. Consequently, the Mg–9Y-1.8Zn alloy exhibits the best fatigue performance under high-stress conditions with an approximate LPSO phase content of 23.7%. Meanwhile, the Mg–9Y–3.1Zn alloy, with an LPSO phase content of around 34.9% under low-stress conditions, demonstrates the best fatigue performance.

Influence of Zn Addition on the Aging Precipitate Behavior and Mechanical Properties of Al-Cu-Li Alloy.

In the present work, the effect of Zn on the aging precipitates and mechanical properties of Al-Cu-Li alloys was investigated by Vickers hardness, tensile tests, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results indicated that the addition of Zn reduced the activation energy of the T1 phase and makes it easier to precipitate. The activation energy of the T1 phase, which was 107.02 ± 1.8 KJ/mol, 94.33 ± 1.7 KJ/mol, 90.33 ± 1.7 KJ/mol and 90.28 ± 1.6 KJ/mol for 0Zn, 0.4Zn, 0.8Zn and 1.2Zn alloy, respectively. The area number density of the T1 precipitate ranged from 97.0 ± 4.4 pcs/μm2 to 118.2 ± 2.8 pcs/μm2 as the Zn content increased from 0 to 1.2 wt.%. Consequently, the addition of Zn promoted the precipitation of the T1 phase. Therefore, the peak hardness and tensile strength of the alloy also increased with the increase in the Zn content, and the hardness of the alloy with Zn content of 1.2 wt.% increased by 16.5 ± 1.4 HV; meanwhile, the ultimate tensile strength increased by 46.5 ± 2.5 MPa. Therefore, the area number density of precipitates increased and improved the strength of the Zn-containing alloy.

Dynamic precipitation and twinning-induced dynamic recrystallization in Mg–6Al–3Sn–1Zn alloy during multi-pass high-speed rolling

Ultrafine-grained microstructure was successfully obtained in Mg–6Al–3Sn–1Zn (ATZ631) alloy by multi-pass high-speed rolling (HSR) at a rolling speed of 1100 m/min and a rolling temperature of 400 °C. The grain refinement mechanism of ATZ631 alloy during HSR was investigated, which is attributed to mechanically fragmented grains and twinning-induced dynamic recrystallization (TDRX). During the initial stages of rolling, the initial coarse grains are refined by the intersection of twins. With increasing strain, the grain refinement mechanism is the typical dynamic recovery and TDRX. In general, twins are filled with a high density of dislocations and nano-sized precipitates at the dislocations, which can accelerate DRX by increasing the driving force or particle-stimulated nucleation (PSN) within the twins. Subsequently, the coarse grains are refined by forming fine DRXed grains via dislocation entanglement, dislocation rearrangement, and dislocation absorption. As the process proceeds, grain boundaries (GBs) migration is suppressed by the precipitates at the GBs of new DRXed grains. Thus, the growth of the DRXed grains can be inhibited. Finally, ultrafine-grained microstructure with an average size of ∼116 nm is obtained. Moreover, the new grains formed by TDRX exhibit random orientation during this process, indicating that the basal texture gets effectively weakened by increasing the fraction of DRXed grains. These findings bring forward the microstructural evolution during dynamic precipitation and DRX, thus providing a novel notion for improving microstructures and grain refinement in Mg alloys.

Biodegradable Zn–Mn–Li alloy with a promising balance of mechanical property and corrosion resistance

To address the current issues of brittleness and lower mechanical performance for Zn alloys, the Zn–Mn–Li system that has significant potential for enhancing strength and toughness is selected for the design, fabrication, and investigation. Li and Mn are selected as alloying elements, and a series of Zn-0.4Mn-xLi alloys are prepared. A comprehensive study of as-cast alloys is conducted on the microstructure, mechanical properties, and corrosion behavior. The results reveal that the initially precipitated β-LiZn4 phase in the as-cast Zn-0.4Mn-xLi alloys gradually transforms into a β-LiZn4/Zn lamellar structure with the increase of Li content. The β-LiZn4/Zn lamellar structure significantly contributes to the strength of the alloy. The as-cast Zn-0.4Mn-0.8Li alloy exhibits optimal mechanical strength, with yield strength and ultimate tensile strength of 203.2 ± 8.9 MPa and 271.5 ± 20.0 MPa, respectively. Electrochemical and immersion experiments indicate a dense Li-rich corrosion product layer formed on the alloy surface suppresses the generation of pitting corrosion and enhances the corrosion resistance of the alloy. These results manifest that the Li content of the Zn–Mn–Li alloy has a significant influence on the performance, such as the microstructure, mechanical properties, and corrosion behavior. According to the results of mechanical properties and corrosion behavior, Zn-0.4Mn-0.8Li alloy exhibits an optimal comprehensive performance, which provides valuable insight for the development of superior Zn–Mn–Li alloys.

Toward high strength and large strain hardening Zn alloys via a novel multiscale-heterostructure strategy

Zn alloy has attracted much attention as a biodegradable material for biomedical applications. However, due to the significant strain softening of Zn alloys, how to break the bottleneck of synergistic yield strength and uniform elongation is an urgent problem to be solved. In this work, a Zn-2.3Cu-0.8Mn (wt.%) alloy was fabricated via low-temperature extrusion and annealing at 330 °C for 1 h to attain dual heterostructures with bimodal grains and multi-scale second phases, focusing on the effect of heterostructure on the mechanical properties. Uniaxial tensile test and loading-unloading-reloading test were applied to reveal the mechanical properties of the Zn-2.3Cu-0.8Mn alloy, while scanning electron microscope, electron backscatter diffraction, and transmission electron microscope were used to characterize its microstructure. Compared with the as-extruded alloy with uniform and fine grains, 330–1 alloy achieves a better combination of strength and uniform elongation (yield strength: 287.8 ± 8.5 MPa, ultimate tensile strength: 321.4 ± 6.8 MPa, and uniform elongation: 14.2 ± 1.8%). The high strength was primarily attributed to the coordination of grain boundary strengthening, hetero-deformation induced strengthening, Orowan strengthening, and dislocation strengthening. Besides, the coarse grains, twinning, as well as the suppression of grain boundary sliding and phase boundary sliding promoted dislocation proliferation and storage capacity, thereby improving work hardening capacity. The large strain hardening capacity was responsible for excellent plasticity. This study provides a feasible strategy for the design of Zn-based alloys with an excellent combination of high strength and strain hardening capacity.