Zinc-based Alloy Research Articles

Severe plastic deformation of Zn and Zn-based alloys

There has been much research on zinc and its alloys for being used in different industries and applications, mainly due to their low cost, availability, good wear resistance and mechanical properties. Moreover, zinc alloys have emerged as the latest advancement in the field of biodegradable metals, offering a more sustainable option with their moderate corrosion rate when compared to other biodegradable metals like magnesium and iron-based alloys. Nevertheless, mechanical properties of zinc alloys typically fall below the necessary levels for use in load-bearing implant applications. In this regard, severe plastic deformation serves as a distinctive technique to enhance the mechanical characteristics of zinc-based alloys, all while keeping the chemical composition intact. In addition to mechanical properties, and as is discussed in this article, SPD can affect other properties of Zn alloys, including biological and corrosion behavior. Over the past few years, extensive studies have been conducted to explore how various SPD processes impact the properties of zinc and its alloys. In this study, the main effects of SPD on the microstructure, mechanical properties, superplastic behavior, and corrosion of zinc and zinc allots together with the underlying mechanisms are reviewed.

Preparation, Mechanical Properties, and Degradation Behavior of Zn-1Fe-xSr Alloys for Biomedical Applications.

As biodegradable materials, zinc (Zn) and zinc-based alloys have attracted wide attention owing to their great potential in biomedical applications. However, the poor strength of pure Zn and binary Zn alloys limits their wide application. In this work, a stir casting method was used to prepare the Zn-1Fe-xSr (x = 0.5, 1, 1.5, 2 wt.%) ternary alloys, and the phase composition, microstructure, tensile properties, hardness, and degradation behavior were studied. The results indicated that the SrZn13 phase was generated in the Zn matrix when the Sr element was added, and the grain size of Zn-1Fe-xSr alloy decreased with the increase in Sr content. The ultimate tensile strength (UTS) and Brinell hardness increased with the increase in Sr content. The UTS and hardness of Zn-1Fe-2Sr alloy were 141.65 MPa and 87.69 HBW, which were 55.7% and 58.4% higher than those of Zn-1Fe alloy, respectively. As the Sr content increased, the corrosion current density of Zn-1Fe-xSr alloy increased, and the charge transfer resistance decreased significantly. Zn-1Fe-2Sr alloy had a degradation rate of 0.157 mg·cm-2·d-1, which was 118.1% higher than the degradation rate of Zn-1Fe alloy. Moreover, the degradation rate of Zn-1Fe-xSr alloy decreased significantly with the increase in immersion time.

Investigation of Biodegradable Zinc-Based Alloy with Varying Compositions of Aluminum and Copper for Orthopedic Applications

Investigation of Biodegradable Zinc-Based Alloy with Varying Compositions of Aluminum and Copper for Orthopedic Applications

Nanoparticle-Enabled Zn-0.1Mg Alloy with Long-Term Stability, Refined Degradation, and Favorable Biocompatibility for Biodegradable Implant Devices.

Zinc-based alloys, specifically Zn-Mg, have garnered considerable attention as promising materials for biodegradable implants due to their favorable mechanical strength, appropriate corrosion rate, and biocompatibility. Nevertheless, the alloy's lack of mechanical stability and integrity, resulting from ductility loss induced by age hardening at room temperature, hampers its practical bioapplication. In this study, ceramic nanoparticles have been successfully incorporated into the Zn-Mg alloy system, leading to a significant improvement in long-term stability as well as mechanical strength and ductility. In addition, this study represents the first investigation of Zn-based nanocomposites both in vitro and in vivo to comprehend the influence of nanoparticles on the degradation behavior and biocompatibility of the Zn system. The findings indicate that the incorporation of WC nanoparticles effectively refines and stabilizes the degradation behavior of Zn-Mg without negatively impacting the cytocompatibility of the alloy. The subcutaneous implantation and femoral implantation further prove the benefits of nanoparticle incorporation and found no negative effects. Collectively, Zn-Mg-WC nanocomposites yield great potential for implant usage.

Mechanical properties and stability of hot rolled Zn-0.8Mg alloy

Insufficient mechanical strength and mechanical instability are important factors limiting the application of zinc-based alloys as biodegradable materials. Currently, alloying and plastic deformation are effective methods to improve material properties. Therefore, this paper investigates the effect of hot rolling process on the mechanical properties and stability of Zn-0.8Mg alloys. The results show that after hot rolling, the internal grain of Zn-0.8Mg alloy is refined, the second phase is precipitated, the weaving strength is enhanced, and the overall mechanical properties are significantly improved. The contribution of deformation strengthening can reach about 90 %. The tensile strength, yield strength, and elongation of the alloy were 312.3 MPa, 249.5 MPa, and 15.6 % (141.72 %, 155.96 %, and 189.96 %, respectively) at a rolling volume of 70 %, which meets the clinical criteria for degradable material implants. However, this treatment reduced the stability of the mechanical properties of the Zn-0.8Mg alloy. During natural ageing, a small amount of Mg2Zn11 phase precipitated inside the alloy, reducing the elongation. Compared with cast alloys, hot rolled alloys have higher grain boundary density, which accelerates the precipitation of secondary phases, leading to more pronounced changes in the mechanical properties of the alloys after hot rolling.

Influence of heat treatment on the microstructure evolution and corrosion performance of biodegradable Zn-Mg alloys

Zinc and zinc-based alloys have garnered increasing attention as biodegradable materials due to their excellent mechanical properties, lower degradation rates compared to magnesium, and favorable biocompatibility. This study investigates the impact of homogenization treatment on the microstructure and corrosion behavior of Zn-Mg alloys using scanning electron microscopy, X-ray diffraction, hardness testing, and accelerated corrosion immersion tests. The results reveal that homogenization treatment induces the fusion of eutectic cells within the alloys, causing significant morphological alternations in the eutectic structure and varying proportions of the Mg2Zn11 phase, These changes notably affect material properties. The raised content of Mg2Zn11 phase in the eutectic structure correlates with higher hardness but reduced corrosion resistance, whereas the reduced Mg2Zn11 phase content leads to enhanced corrosion resistance. Furthermore, in-situ corrosion observations demonstrate that corrosion initiates at the eutectic phase, with corrosion pits forming due to the ion release as corrosion progresses, leading to gradual enlargement of the corrosion pits. In summary, this study provides comprehensive insights into the microstructural changes in Zn-Mg alloys and their impact on corrosion resistance, offering valuable references for their engineering applications.

Process window and mechanical properties for thin magnesium- and zinc-wires in dieless wire drawing

Due to their biodegradable properties, magnesium- and zinc-based alloys are in the focus of interest for numerous medical applications, e.g. in the form of thin wires. To achieve improved processability by using hot forming and to obtain higher diameter reductions per pass, the dieless wire drawing process is presented in this paper. In order to investigate the processability and the resulting mechanical properties, a selection of magnesium- and zinc-alloys as well as process parameters are chosen, and wire manufacturing is carried out using the dieless drawing process. The resulting process windows and mechanical properties for the selected materials are discussed. It is found that the length of the forming zone is an important indicator for the process window and the cross-sectional area reduction accuracy in the dieless wire drawing process. Furthermore, process parameter variations result in a distinct variation of the mechanical properties of the wires, whereas process temperatures close to the wire extrusion temperature result in mechanical properties similar to the as-extruded wires. Good localization of the deformation is found for forming zones of 25–75 mm length at elevated temperatures and cross-sectional area reductions of up to 30% are possible for Z1 and ZX10 in one drawing step.Graphical

Harmonizing microstructures and enhancing mechanical resilience: Novel powder metallurgy approach for Zn–Mg alloys

Zinc alloys are recognised for their excellent biocompatibility and favourable corrosion rates, making them suitable for bioabsorbable implants. However, their mechanical properties necessitate improvement to fulfil the rigorous requirements of biomedical applications. This research focuses on engineering pseudo-harmonic structures within zinc alloys through a comprehensive method combining mechanical alloying, spark plasma sintering, and hot extrusion techniques. This fabrication process results in a composite material characterised by a soft core surrounded by a continuous, three-dimensional, ultrafine-grained hard shell. The experiment involved blending pure zinc with Zn–1Mg alloy powder, leading to the formation of both ductile zinc and fine-grained Zn–1Mg regions. While the Mg2Zn11 intermetallic phase was found to enhance the alloy's mechanical strength, the presence of oxide shells adversely affected the material's properties. The elimination of these shells via hot extrusion markedly improved the alloy's tensile strength, reaching an average value of tensile strength of 333 ± 7 MPa. This study provides significant insights into the material engineering of zinc-based alloys for biodegradable implant applications, demonstrating a viable approach to optimising their mechanical performance.

Effects of Dynamic Flow Rates on the In Vitro Bio-Corrosion Behavior of Zn-Cu Alloy

In the complicated real physiological environment in vivo, body fluids and blood are constantly replenished and move dynamically, and therefore, the dynamic impacts of bodily fluids and blood need to be considered in the evaluation of biodegradable materials. However, little research has been conducted on the impact of dynamic flowing circumstances on the corrosion characteristics of zinc-based alloys, particularly at high flow rates. The effects of various flow rates on the bio-corrosion behavior of the Zn-Cu alloy are thoroughly explored in this study. A model is developed using finite element analysis to investigate the impacts of flow rates and fluid-induced shear stress. The results reveal that the corrosion process of the Zn-Cu alloy is significantly accelerated by a higher flow rate, and a large fluid-induced shear stress caused by the boundary effect is found to promote corrosion. Furthermore, the empirical power function between the average flare rates in Hank’s solution and the corrosion rates of the Zn-Cu alloy is established by numerical simulation. The results provide insightful theoretical and experimental guidance to improve and evaluate the efficacy and lifespan of biomedical zinc-based alloy implants.

Comparative study of zinc base alloy coatings: composition, microstructure, and corrosion resistance

The elemental composition, microstructure and corrosion resistance of three different zinc base alloy coatings (Zn–Ni alloy, Zn–Fe alloy and Zn–Co alloy) electrodeposited with the same complexing agent were studied by using a common zincate bath. The suitable current density is designed through experiments. Under the same current density, Zn–Ni alloy coating, Zn–Fe alloy coating and Zn–Co alloy coating are electrodeposited. The types and contents of microcomponent elements were analyzed by energy dispersive spectroscopy (EDS), the surface structure was analyzed by scanning electron microscopy (SEM), and the corrosion resistance was analyzed by electrochemical techniques (AC impedance, Tafel curve). The results show that the microstructure of Zn–Co and Zn–Fe alloy coatings is similar, the surface of the coatings is flat and the crystal distribution is uniform, but the grain of Zn–Co alloy coatings is obviously larger than that of Zn–Fe alloy coatings. In the electrochemical test part, the AC impedance of Zn–Co alloy coating is much higher than that of Zn–Ni alloy coating and Zn–Fe alloy coating, and the self-corrosion current density is lower than that of Zn–Ni alloy coating and Zn–Fe alloy coating, so it has the best corrosion resistance.

In vitro calibration and in vivo validation of phenomenological corrosion models for resorbable magnesium-based orthopaedic implants

Metallic bioresorbable orthopaedic implants based on magnesium, iron and zinc-based alloys that provide rigid internal fixation without foreign-body complications associated with permanent implants have great potential as next-generation orthopaedic devices. Magnesium (Mg) based alloys exhibit excellent biocompatibility. However, the mechanical performance of such implants for orthopaedic applications is contingent on limiting the rate of corrosion in vivo throughout the bone healing process. Additionally, the surgical procedure for the implantation of internal bone fixation devices may impart plastic deformation to the device, potentially altering the corrosion rate of the device. The primary objective of this study was to develop a computer-based model for predicting the in vivo corrosion behaviour of implants manufactured from a Mg-1Zn-0.25Ca ternary alloy (ZX10). The proposed corrosion model was calibrated with an extensive range of mechanical and in vitro corrosion testing. Finally, the model was validated by comparing the in vivo corrosion performance of the implants during preliminary animal testing with the corrosion performance predicted by the model. The proposed model accurately predicts the in vitro corrosion rate, while overestimating the in vivo corrosion rate of ZX10 implants. Overall, the model provides a “first-line of design” for the development of new bioresorbable Mg-based orthopaedic devices. Statement of significanceBiodegradable metallic orthopaedic implant devices have emerged as a potential alternative to permanent implants, although successful adoption is contingent on achieving an acceptable degradation profile. A reliable computational method for accurately estimating the rate of biodegradation in vivo would greatly accelerate the development of resorbable orthopaedic implants by highlighting the potential risk of premature implant failure at an early stage of the device development. Phenomenological corrosion modelling approach is a promising computational tool for predicting the biodegradation of implants. However, the validity of the models for predicting the in vivo biodegradation of Mg alloys is yet to be determined. Present study investigates the validity of the phenomenological modelling approach for simulating the biodegradation of resorbable metallic orthopaedic implants by using a porcine model that targets craniofacial applications.

Study of biocompatibility and antitumor cytotoxic activity <i>in vitro</i> of Zn – 1 %Mg and Zn – 1 %Mg – 0.1 %Ca alloys strengthened by equal angular pressing

Introduction. The biological activity of potential biodegradable zinc-based alloys that are promising for oncoorthopedics was studied in this work. The alloys were processed by equal-channel angular pressing, which made it possible to increase their strength due to microstructure refinement and the ability to provide the functionality of osteosynthesis, fixed due to the metal structure developed on their basis.Aim. Investigation of effect of equal-channel angular pressing (ECAP) treatment on strength, ductility, degradation rate, biocompatibility in vitro and cytotoxicity against SKOV-3 tumor cells of the Zn – 1 %Mg and Zn – 1 %Mg – 0.1 %Ca alloys.Materials and methods. The Zn – 1 %Mg and Zn – 1 %Mg – 0.1 %Ca alloys in the initial state and after ECAP were used as objects of study, and blood cells of CBA mice were used as model systems. To assess the hemolytic activity, the samples were incubated with red blood cells for 4 and 24 hours at 37 °C, assessing the relative increase in the level of extracellular hemoglobin compared to the intact control. The cytotoxicity of the alloys was assessed by the change in the level of extracellular lactate dehydrogenase (LDH) activity after 24 hours of incubation with mononuclear white blood cells. The study of antitumor cytotoxic activity was carried out on human ovarian cancer cells of the SKOV-3 line in vitro, assessing their survival after 48 hours of incubation with alloy samples using the LDH test.Results. As a result of the studies, it was concluded that the studied alloys after ECAP treatment retained their biocompatibility, since there were no signs of hemolysis and cytotoxicity with respect to blood cells. However, contact with samples of all studied alloys in vitro induced a significant inhibition of the metabolic activity of the ovarian cancer cell culture in comparison with the control. Incubation with alloys samples leads to a decrease in cellular activity by an average of 49 % and 59 % for Zn – 1 %Mg and Zn – 1 %Mg – 0.1 %Ca alloys, respectively. The addition of calcium to the composition of the alloy Zn – 1 %Mg contributed to the growth of antitumor cytotoxic activity.Conclusion. Thus, based on the results of assessing the hemolytic activity and cytotoxicity of the samples, we can conclude that the studied alloys are biocompatible. It was also found that Zn – 1 %Mg and Zn – 1 %Mg – 0.1 %Ca alloys had a pronounced cytotoxic effect on SKOV-3 tumor cells. The obtained data indicate the prospects for the development of a new type of medical devices based on the studied alloys, promising, in particular, for oncoorthopedics: a metal structure developed on their basis can ensure the strength of osteosynthesis, reduce the risk of local recurrence of oncological disease and does not require a second operation to remove the device.

A Study on the Influence of the Electroplating Process on the Corrosion Resistance of Zinc-Based Alloy Coatings

A comprehensive analysis was conducted to examine the crystal phase composition, surface and cross-section morphology, elemental composition, thickness, and corrosion resistance of coatings. X-ray diffraction (XRD) was employed to investigate the texture and crystal phase of the materials while scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were utilized to assess the surface and cross-section structure. Additionally, electrochemical techniques were employed to evaluate the corrosion performance. Compared to DC electroplating, the corrosion potential of pulsed galvanized ferroalloy alloy coating increased from −1031 mV to −1008 mV, and the corrosion current density decreased from 3.122 × 10−5 A∙cm−2 to 0.321 × 10−5 A∙cm−2. Moreover, the corrosion rate value of the coating obtained by the pulse rectifier (0.386 × 10−5 g m−2 h−1) was lower than that obtained by the DC power supply (3.75 × 10−5 g m−2 h−1). Additionally, pulsed electrodeposition reduced the iron content of the coating by 0.7%, thereby enhancing its corrosion resistance and flatness. The impedance parameters of the zinc–iron alloy coating acquired through the 30% duty cycle monopulser process exhibit superior performance compared to DC electroplating. Evidently, the monopulse coating’s structure enhances crystal packing density, augments coating thickness, improves adhesion to the substrate interface, and optimizes grain distribution uniformity. These factors are crucial determinants of the corrosion behavior exhibited by Ze–Fe coating.

Thermodynamic study of the Ca-Cu-Zn ternary system with key experimental measurements

Zinc-based alloys, particularly those alloyed with elements like Ca, Cu, and others, have emerged as promising candidates for biodegradable implants. Therefore, the purpose of this study was to investigate the phase equilibrium relationship of the Ca-Cu-Zn ternary system in the Cu-Zn rich region for Zn-based biodegradable materials development. In this work, 21 and 19 samples were prepared and annealed at the temperatures of 350 and 400 °C, respectively. And Then, these samples were analyzed using analytical techniques including scanning electron microscopy (SEM) coupled with energy dispersion spectroscopy (EDS), electron probe microanalysis (EPMA), and powder X-ray diffraction analysis (XRD). The present obtained results indicate the existence of five regions exhibiting three-phase equilibrium and sixteen regions exhibiting two-phase equilibrium within these two isothermal sections. Additionally, differential scanning calorimetry (DSC) was utilized to determine the phase transition temperatures of alloys with constant values of 12 at% Cu and 40 at% Ca, respectively. Moreover, the CALPHAD method was employed to optimize the thermodynamic parameters of the phases of Ca-Cu-Zn ternary system. The model of the liquid phase was performed using the modified quasi-chemical model (MQM). The compound energy formalism (CEF) model was used to represent the Gibbs free energy of the solid phases. Finally, the experimental measured results could be reproduced well using the present obtained thermodynamic parameters.

Surface gradient structure induced by Cu ion implantation optimizes the degradation behavior of biodegradable Zn–Cu–Li alloy

Surface modification is a crucial method for regulating the degradation behavior of biomedical zinc-based alloys in consideration of clinical safety. In this work, Cu ion implantation was introduced for Zn–4Cu–0.02Li. The results indicated that a gradient modified layer formed, which was composed of three regions, namely, a 70-nm element implanted layer, a 600-nm nanocrystalline layer, and a 2-μm columnar crystal layer. The modified layer reduced corrosion within one month and transformed the localized corrosion into the uniform corrosion mode. Its hierarchical degradation process induced the controlled degradation. Additionally, Cu ion implantation enhanced the inhibitory effect on S. aureus.

Microstructure and mechanical properties of friction stir processed Zn-Mg biodegradable alloys

Magnesium, iron and zinc-based alloys are potential metallic biodegradable alloys for bioimplant applications. The issues of hydrogen evolution along magnesium’s surface and the release of bulky corroded products of iron alloys during its usage necessitated to look for an alternate alloy system for biodegradable implant applications. Zn-Mg alloy is one such alternate alloy that is widely explored by several researchers. The typical cast microstructure of Zn-Mg alloy contains pro-eutectic α-Zn and eutectic mixture of α-Zn and Mg2Zn11. The cast alloy exhibits poor ductility as the intermetallic Mg2Zn11 phase exists only in eutectic mixture. Therefore, the cast alloys were subsequently processed through hot rolling, hot extrusion and rarely through severe plastic deformation to enhance the mechanical properties. In the current study, probably for the first time, friction stir processing (FSP) has been used to refine the microstructure of Zn-Mg alloys with an intention to enhance the mechanical properties. Indeed, it was a challenge to friction stir process the Zn alloys through friction stir processing, as they have poor ductility (< 10 %) in as-cast condition. By choosing tool rotational speed that can impart significant heat input to the processed regime, this study demonstrated successful FSP of Zn and Zn-(0.5, 1.0 & 2.0) wt% Mg alloys. The pure-Zn and Zn-Mg alloys are FSPed using constant tool traverse speed of 20 mm/ min and variable rotational speeds of 560, 710 and 900 rpm. Hardness of as-cast Zn was 32 VHN whereas addition of 2 % Mg increased it to 105 VHN. Hardness of zinc increased to 39 VHN after FSP using 560 rpm; at the same time, further increase of rotational speed retained the hardness around 40 VHN. On the other hand, hardness of Zn-Mg alloys significantly improved after FSP. Interestingly, hardness of alloys increased with the rotational speed. Usually, increase of rotational speed increases heat input in to the processed regime thus assists the development of coarse microstructure results in hardness degradation. An opposite trend has been observed in the current study. The reasons for this notable observation are found to be refinement of microstructure and redistribution of Mg2Zn11 phase throughout α-Zn matrix that happened during FSP.

The effect of slow strain rate tension and cyclic loading on biodegradable Zn–2%Fe–0.8%Mn alloy in a simulated physiological environment

Zinc-based alloys have gained increased interest as biodegradable structural materials for medical applications due to their adequate biocompatibility, crucial roles in many physiological functions and attractive antibacterial properties. However, the major drawbacks of zinc alloys relate to their inadequate mechanical properties and tendency to provoke fibrous encapsulation due to relatively high standard potential. Based on the promising effect of Mn on properties of Zn-based alloys, the present study aimed at evaluating the suitability of Zn–2%Fe–0.8%Mn alloy as a potential biodegradable implant under in-vitro conditions. This evaluation focused on the passivation characteristics as determined by cyclic potentiodynamic polarization analysis, immersion test, stress corrosion behavior by slow strain rate testing (SSRT), corrosion fatigue and direct cell viability in terms of cell adherence and proliferation after 24 and 48 h post incubation. The results showed that the addition of 0.8%Mn to the base Zn–2%Fe alloy improves the specific strength and direct cell viability characteristics while decreasing the effectiveness of natural passivation processes. The main overall effect of adding 0.8%Mn to Zn–2%Fe alloy were (i) reduced stress corrosion resistance in terms of time to failure at a low strain rate (2.5 × 10−7 s−1) from 285 h to 205 h (ii) reduced corrosion fatigue endurance from 4,997,285 cycles to only 377,552 cycles to failure at the lowest load of 30 MPa.

Spatiotemporal evaluation of plasma parameters and assessment of LTE during LIBS analysis of a zinc-based alloy

Spatiotemporal evaluation of plasma parameters and assessment of LTE during LIBS analysis of a zinc-based alloy

The Influence of Manganese Addition on the Properties of Biodegradable Zinc-Manganese-Calcium Alloys.

This study focuses on the preparation and characterization of zinc-based alloys containing magnesium, calcium, and manganese. The alloys were prepared by the melting of pure elements, casting them into graphite molds, and thermo-mechanically treating them via hot extrusion. The phase compositions of the samples were analyzed using X-ray diffraction technique and SEM/EDX analysis. The analysis confirmed that in addition to the Zn matrix, the materials are reinforced by the CaZn13, MgZn2, and Mn-based precipitates. The mechanical properties of the alloys were ascertained by tensile, compressive, and bending tests, measurement of the samples microhardness and elastic modulus. The results indicate that an increase in Mn content leads to an increase in the maximum stress experienced under both tension and compression. However, the plastic deformation of the alloys decreases with increasing Mn content. This study provides valuable insights into the microstructural changes and mechanical behavior of zinc-based alloys containing magnesium, calcium, and manganese, which can be used to design alloys for specific biomedical applications.

Preparation and Basic Characterization of Novel Zinc-based Alloys for Intracorporeal Implants

Preparation and Basic Characterization of Novel Zinc-based Alloys for Intracorporeal Implants