WE43 Alloy Research Articles

Preparation of WE54 alloy with excellent mechanical properties by hard-tube rotary swaging and aging treatment

Preparation of WE54 alloy with excellent mechanical properties by hard-tube rotary swaging and aging treatment

Effect of glucose concentration on the corrosion behaviour of WE43 alloy in Hank’s balanced salt solution

Effect of glucose concentration on the corrosion behaviour of WE43 alloy in Hank’s balanced salt solution

Preparation of nanoprecipitates and ultrafine grains for WE43 alloy to enhance mechanical properties by pre-aging treatment prior to extrusion

Preparation of nanoprecipitates and ultrafine grains for WE43 alloy to enhance mechanical properties by pre-aging treatment prior to extrusion

RESORBABLE WE43 VERSUS TITANIUM FIXATION DEVICES- EVALUATION OF TREATMENT OUTCOMES: A SYSTEMATIC REVIEW

Background: Internal fixation of mandibular fractures with Titanium (Ti) plates has become the gold standard for treatment in the adult population. Unfortunately, Ti plates had a tendency to undergo corrosion causing inflammation of surrounding bone that often led to failure of treatment. Magnesium (Mg) based newer materials such as WE43 alloy have been studied extensively for its ability to resorb in the presence of living tissue. Mg based WE43 alloy has demonstrated superior corrosion resistance and mechanical properties comparable to standard Titanium devices. The aim of this systematic review was to know whether WE43 based fixation devices can be used as an alternative to Ti based fixation devices for osteosynthesis. Materials and Methods: PubMed, Cochrane, Google Scholar, Web of Science, were searched to find the studies comparing the WE43 fixation devices and Ti based fixation devices for osteosynthesis. No filters were applied. Search terms related to WE43, titanium, fixation, osteosynthesis, corrosion resistance, fracture fixation, complications of treatment, etc, were used to search relevant studies. Data extraction, quality assessment, and summary synthesis for treatment outcomes including corrosion resistance,stability, osteosynthesis, adverse effects were carried out. Results: 5 studies consisting of 3 in-vivo animal studies and 2 clinical trials were included after the screening of search results. In the animal studies, i)16 rabbit specimens were divided into 2 groups -Group I received Ti based implants, while Group II received Mg based WE43 implants. ii)10 beagle dogs were divided into 2 groups and evaluated at 4, 12, and 24 weeks after implant placement. iii)18 hemi mandibles of sheep were tested to check the outcome of fracture fixation between Mg and Ti based fixation devices. Group I used Ti1.0, Group II used Mg 1.75, and Group III used Mg 1.5. In the clinical trials, i) fixation of mandibular head fracture was done in 31 using WE43 screws and 29 patients using Mg screws and ii) 11 patients treated with Mg compression screws and 10 patients with Ti compression screws. Conclusions: Comparison of properties of WE43 with Ti in the animal models has shown a non-inferiority of the Mg based material. Biomechanically, the human studies revealed promising results concerning the use of WE43 as a potential alternative to Ti in fracture fixation. Further evaluation is warranted under biomechanical loading conditions to verify the clinical performance of the material.

Enhanced corrosion resistance, mechanical properties, and biocompatibility of N-DLC coatings prepared on WE43 alloy via FCVA technology

Enhanced corrosion resistance, mechanical properties, and biocompatibility of N-DLC coatings prepared on WE43 alloy via FCVA technology

Characterization of cast rare earth WE43 magnesium alloy and parameter optimization for wire electrical discharge machining using TOPSIS & COPRAS

The manuscript examines the fabrication of rare earth magnesium alloy WE43, and its performance under wire electrode discharge machining (WEDM) conditions. It focuses on WEDM parameter optimization using multi criteria decision making (MCDM) techniques. WE43 alloy manufactured using casting method were characterized using advanced microscopy and spectroscopy techniques to analyze the microstructure, phase structure, and mechanical properties. WEDM experiments explores the effect of pulse current, pulse-on time, pulse-off time, and voltage on the material removal rate (MRR) and surface roughness (SR). MCDM methods, like Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Complex Proportional Assessment (COPRAS), are used to identify optimal machining conditions, with both approaches agreeing on the same optimal parameter set: pulse current of 15 A, pulse-on time of 5 µs, pulse-off time of 15 µs, and voltage of 30 V. This combination produces the best balance between MRR and SR, confirmed by additional experiments. The findings highlight the potential of the WE43 alloy for applications requiring precision machining, offering valuable insights for industrial use and future research.

Predicting the evolution of texture and grain size during deformation and recrystallization of polycrystals using field fluctuations viscoplastic self-consistent crystal plasticity

This paper advances a recent formulation of a field fluctuations viscoplastic self-consistent (FF-VPSC) crystal plasticity model to predict not only the evolution of texture in polycrystalline metals undergoing deformation and recrystallization but also the evolution of grain size. The model considers stress and lattice rotation rate fluctuations inside grains to calculate intragranular misorientation spreads. The spreads are used for modeling of grain fragmentation during deformation and grain nucleation during recrystallization enabling the predictions of concomitant evolution of texture and grain size distributions. The evolutions of textures and grain size distributions are first simulated for commercially pure Cu undergoing severe plastic deformation (SPD) in high pressure torsion to agree well with corresponding experimental data. Next, the evolution of texture and grain size in an aluminum alloy (AA) 5182-O after simple tension and static recrystallization are predicted and compared with experiments. Finally, the predictions of texture and grain size distributions in a magnesium alloy WE43 undergoing a thermo-mechanical loading in the dynamic recrystallization regime are presented and compared with experiments. After validation, the model is coupled with the implicit finite element method (FEM) via a user-material subroutine (UMAT) in Abaqus to facilitate modeling of complex boundary conditions and geometries. The multilevel approach is referred to as FE-FF-VPSC in which every integration point embeds the FF-VPSC constitutive law, considering texture evolution and the directionality of deformation mechanisms operating at the single crystal level. FE-FF-VPSC is applied to simulate a sequence of rolling, recrystallization, and deep drawing of a circular cup of AA6022-T4. The simulated processing sequence demonstrates the versatility of the simulation framework developed in the present paper in not only predicting texture and grain size evolution and phenomena pertaining to behavior of materials but also geometrical shape changes important for the optimization of metal forming processes. To this end, the effects of initial texture and underlying anisotropy on the formation of earing profiles during deep drawing are simulated and discussed.

Transmission Electron Microscope Characterizations of the Localized Corrosion Behavior of Biodegradable ZX21 Mg Alloy in Hanks’ Balanced Salt Solution

Magnesium (Mg) alloys attract a lot of attention as next-generation biodegradable implant materials due to their excellent biocompatibility and unique biodegradability. By utilizing Mg alloys as implants, Mg alloys can be degraded naturally in the human body, avoiding the second removal surgery. In addition, Mg alloys are promising for orthopedic applications because of their similar density and mechanical properties to bones, which mitigate the stress shielding effect. Among various Mg alloy systems, the ZX-series Mg alloys, which contain zinc (Zn) and calcium (Ca), show great potential for orthopedic applications since Zn and Ca are essential for metabolism and bone regeneration and improve the mechanical strength of the alloys. However, localized corrosion of a ZX-series Mg alloy was reported in our previous study [1], leading to a faster degradation rate and possible premature failure of the implant.To further study the origin and detailed mechanism of the localized corrosion behavior of ZX-series Mg alloys in simulated physiological environments, transmission electron microscope (TEM) characterizations were performed on a ZX21 (Mg-2.15 wt%Zn-0.97 wt%Ca) Mg alloy before and after corrosion in a Hanks’ balanced salt solution (HBSS) at 37°C. Two second phases, Ca2Mg6Zn3 and Mg2Ca, were found adjacent to each other in the cast ZX21 alloy. The potential difference between the two second phases leads to microgalvanic corrosion and the preferential dissolution of the lower-potential Mg2Ca, initiating localized corrosion on the alloy surface. The localized corrosion propagates a few micrometers deep in the alloy and underneath the surface corrosion film. By selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS) analysis in TEM, the corrosion products in the propagating localized corrosion regions are primarily composed of Mg(OH)2, which is different from the surface corrosion film (Mg(OH)2 + CaHPO4·2H2O) formed on the alloy surface [1]. Furthermore, the presence of Cl signal in the localized corrosion regions indicates that the Cl- ions in HBSS promote the propagation of localized corrosion.[1] P.W. Chu et al., Corrosion Behavior and Microstructure of the Surface Corrosion Film of Biodegradable WE43 and ZX21 Mg Alloys in Hanks’ Balanced Salt Solution, Materials Chemistry and Physics, vol. 312, pp. 128609-128620, 2024.

Effect of heat treatment on microstructure and mechanical properties of WE43 alloy fabricated by wire arc additive manufacturing

Heat treatment is an effective method to improve the mechanical properties of Wire Arc Additive Manufacturing (WAAM) WE43 alloy. This study investigates the effects of heat treatment on the microstructure and mechanical properties of the WE43 alloy processed by WAAM. The as-deposited samples exhibit a uniform equiaxed crystal structure, with grain size gradually increasing as the number of deposited layers grows. The as-deposited microstructure comprises eutectics and a small amount of cubic phases, and the phase content escalates as the amount of deposited layers increases, influenced by the cumulative effect of multiple thermal cycles. At lower solid solution temperatures (480 °C × 8 h), most of the eutectic phase remains undissolved. During tensile testing, undissolved eutectics tend to cause stress concentrations, leading to cracks that result in sample fractures, negatively affecting the mechanical properties. At higher solid solution temperatures (520 °C × 8 h), most of the eutectic dissolves, but abnormal grain coarsening (AGC) in the interlayer fine-grain region occurs, causing a significant reduction in the sample's mechanical properties. After solid solution treatment at 500 °C for 8 h, only a small amount of eutectics remains undissolved, and the AGC phenomenon is not observed, resulting in an optimal solid solution effect. Subsequently, after aging treatment at 225 °C for 18 h, dense nanoscale β′′ phases precipitated within the alloy grains, significantly improving the mechanical properties. The samples achieved optimal performance, with UTS, YS, and EL of 323 ± 15.2 MPa, 225 ± 11.3 MPa, and 8.4 ± 1.1 %, respectively.

Insights into heat treatments of biodegradable Mg-Y-Nd-Zr alloys in clinical settings: Unveiling roles of β' and β1 nanophases and latent in vivo hydrogen evolution

Heat treatment serves as a viable strategy to effectively mitigate the intense corrosion of biodegradable WE43 alloys. However, limited comprehension of the passivation mechanisms underlying heat treatment and the dilemma to quantitatively examine the evolution of hydrogen gas in vivo introduce uncertainties in designing heat treatments for developing clinically applicable WE43. This work aims to advance this knowledge by applying cutting-edge atom probe tomography to provide atomic-scale insights into the passivation roles of rare earth (RE)-rich β1 (Mg3(Y, Nd)) and β' (Mg12NdY) nanophases induced by T6 heat treatment at 250 °C, and employing machine learning-based image analysis techniques to quantitatively unveil WE43’s in vivo gas evolution during a 12-week implantation. It was found that nanosized β1 and β' phases can effectively improve WE43′s corrosion resistance by inducing an accelerated passivation effect on the surface and confining the distribution of hydrogen ions in the matrix. Female rats presented slightly higher corrosion rates than male rats in weeks 1 and 4 but lower hydrogen gas volumes in vivo, while male rats possessed a superior ability to metabolise hydrogen gas in vivo. Notably, latent gas evolution against the corrosion rates was found which peaked at week 4 and subsided at week 12 despite the gradually decreased corrosion rates from week 1 to 12. This study offers insights for engineering heat treatments to develop clinically applicable WE43 with acceptable corrosion rates and in vivo gas generation at various implantation stages. Statement of SignificanceThe study aimed to reveal the role of β1 and β' nanophases on the good corrosion resistance of WE43. The influence of these nanophases on WE43′s corrosion performance has not been totally understood. Similarly, the understanding of hydrogen gas evolution as it relates to the magnesium implant's corrosion rate lacks clarity. Atom probe tomography (APT) indicates β1 and β' nanophases trap hydrogen, removing H2 from the lattice and disabling its catalytic role in Mg oxidation. Machine learning-aided analyses of computed tomography (CT) scan images indicate latent gas evolution, contradicting the monotonic in vivo H2 evolution that is widely accepted.

Study on the influence of corrosion degree on the high-temperature oxidation and combustion characteristics of AZ91, WE43 and ZE10 magnesium alloys

Based on magnesium alloy materials, different degrees of corrosion occur on the surface during use, and the corrosion state significantly affects its high-temperature oxidation and combustion characteristics. This study examines various corrosion conditions, investigates the impact of different corrosion levels on the combustion characteristics of magnesium alloys, and analyses the adsorption performance, state density, and oxygen atom diffusion barrier of alloy elements in AZ91, WE43, and ZE10 magnesium alloys based on first-principles calculations. It reveals the mechanism of the impact of each alloy element on the surface oxide film of magnesium alloys and explains the principles of the experimental results. The results indicate that with increasing corrosion time, temperature, and pressure, the time for the surface oxide film to rupture significantly decreases. In the six magnesium alloy systems of quantum calculations, the Mg–Re structure exhibits the strongest stability. According to adsorption energy calculations, the Mg–Al and Mg–Y systems show the best oxygen adsorption performance. Magnesium alloys doped with Y and Ce elements have the highest oxygen atom diffusion barrier. Hence, magnesium alloy systems doped with Y and Ce elements have a dense surface oxide film that remains undamaged even at very high temperatures, demonstrating excellent high-temperature corrosion resistance and providing an explanation for the experimental results.

Variation of Corrosion Characteristics and Tensile Performances of WE43 Alloy Under Marine Atmospheric Environment.

This study aims to examine the variation in corrosion characteristics and tensile properties of WE43 magnesium alloy in an actual marine atmospheric environment by means of outdoor exposure tests. The macroscopic corrosion morphology, microstructure, and tensile properties were analyzed. The results indicated that WE43 alloy will corrode rapidly during exposure under marine atmospheric environmental conditions, resulting in a loose and porous Mg(OH)2 layer on the surface. The Mg matrix was mainly consumed as an anode, leading to the occurrence of corrosion pits. With the increase in exposure time, both the tensile strength and plasticity of WE43 alloy gradually deteriorated. After exposure for six months, the elongation and area reduction were significantly reduced, with a reduction ratio of more than 50%. After 18 months of exposure, the ultimate strength of the alloy decreased from 359 MPa to 300 MPa. According to an analysis of fractures in the alloy, the corrosion pits on the sample surface were the main reason for the decrease in tensile properties.

Multifunctional zinc oxide loaded stearic acid surfaces on biodegradable magnesium WE43 alloy with hydrophobic, self-cleaning and biocompatible attributes

Biodegradable Mg alloys are one of the most promising materials for implant applications, for which the widespread use is hampered by rapid degradation in physiological environment. The present study explores the development of a novel zinc-oxide (ZnO) loaded stearic acid (SA) coating on medical grade WE43 alloy using a facile, and environment-friendly technique for promising biomaterial surface applications. Morphology and chemical analyses reveal the development of a layered coating surface with uniformly dispersed ZnO nanoparticles in SA matrix. The developed coating exhibits hydrophobic performance (contact angle of 135°) along with the retainment of hydrophobicity under varying chemical (acidic pH of 1 and basic pH of 13) and mechanical (post scratch testing and peel-off studies) conditions. The observed surface water repellency facilitates self-cleaning performance pointing towards its efficacy against potential biofilm formation. The developed coating demonstrates superior resistance against surface degradation during immersion studies in phosphate buffer saline solution (pH = 7.4) and better cell viability with MG-63 (human osteosarcoma) cell line. The approach presented here sets a platform for the development of efficient coatings on biodegradable WE43 alloys surfaces for potential biomaterial technologies.

Fabrication of high-performance biomedical rare-earth magnesium alloy-based WE43/hydroxyapatite composites through multi-pass friction stir processing

Magnesium-based composites with bioactive ceramic particles addition are promising materials for biomedical implant applications. Nevertheless, the agglomeration of bioactive ceramic particles remains a challenge for fabricating high-performance biomedical magnesium-based composites. Herein, a novel high-performance biomedical rare-earth magnesium alloy-based WE43/hydroxyapatite (HA) composite is successfully fabricated via multi-pass friction stir processing (MP-FSP). Systematic investigations reveal that MP-FSP leads to a uniform distribution of HA particles and efficient elimination of defects. The microstructural analysis shows a significant grain refinement in the WE43 alloy from 49.4 μm to 2.4 μm under triple-pass FSP. The mechanical properties of the composite are enhanced significantly under triple-pass FSP, with yield strength, ultimate tensile strength, and elongation reaching 236.2 MPa, 278.6 MPa, and 14.2% respectively. Corrosion resistance is also improved, with a 30% reduction in the corrosion rate in SBF solution compared to the unprocessed alloy. Moreover, the MP-FSP fabricated composites exhibit superior corrosion-wear resistance, characterized by slight abrasive wear compared to the abrasive wear and severe pitting corrosion observed in the base WE43 alloy. These improvements are attributed to the synergistic effects of grain refinement, dispersion strengthening, enhanced interfacial bonding, and texture modification. Overall, these findings provide significant insights into the fabrication of magnesium-based composites for biomedical implant applications, highlighting the effectiveness of MP-FSP in enhancing both mechanical and corrosion-related properties.

Surface modification of WE43 Mg alloy via combination of cold spray and micro-arc oxidation for wear related applications at high temperatures

This study investigates the high temperature wear behaviour of a WE43 Mg alloy after covering it with single and dual layer coatings. For this purpose, cold spray and micro-arc oxidation processes were employed individually and sequentially. Single-layer coatings fabricated by cold spray and micro-arc oxidation processes were Al/Al2O3 composite and MgO-based ceramic, respectively. Sequential application of cold spray and micro arc oxidation processes induced dual layer coating upon synthesizing an external Al2O3–based layer over the Al/Al2O3 composite layer. Results of the wear tests conducted under the load of 2 N revealed the superior resistance of the dual layer coated sample against the rubbing action of the counterface compared to single layer coatings. Thus, the presence of a relatively hard and tough external Al2O3-based layer over the Al/Al2O3 composite layer sustained protection up to the temperature of 320 °C, where the dominant wear mechanism was fatigue wear. However, the increase in the test temperature to 350 °C caused detachment of the external Al2O3-based layer. Reduction of the wear test load from 2 to 1 N resulted in the remaining of external Al2O3-based layer intact with the underlying Al/Al2O3 composite layer even at a test temperature of 350 °C. It is therefore concluded that the combination of cold spray and micro-arc oxidation processes is promising to broaden the reliable use of WE43 and other Mg alloys in wear related applications at high service temperatures.

Microstructure-induced anisotropic biocorrosion response of laser additive manufactured WE43 alloy

The microstructure and corrosion of laser-processed WE43 was studied. Results suggest that multi-factors like grain structure, crystallographic defect, and precipitate distribution result in an anisotropic corrosion response. XY plane with high crystal defect densities offers more sites for pitting corrosion. Filiform corrosion is detected on both XY plane and XZ plane, where Zr-rich and RE-rich precipitate distribution plays an essential role in corrosion initiation and propagation. The enrichment of Zr around filament corrosion promotes local micro-galvanic corrosion. Notably, the XY-plane, with continuous distribution and extended scanning trajectory edge, is particularly susceptible to filiform corrosion as compared with XZ-plane.

Effect of multi-directional compression on microstructure and mechanical properties of Tip/WE43 composite

Titanium (Ti) particle-reinforced Mg-4Y–2Nd-1Gd-0.5Zr (WE43) magnesium (Mg) matrix composite (Tip/WE43) was prepared via vacuum hot-pressing sintering. The multi-directional compression (MDC) treatment significantly enhanced the material's strength, and the MDC 6 wt% Tip/WE43 composite exhibits exceptional mechanical properties, with a yield strength (YS) of 255 MPa, ultimate tensile strength (UTS) of 316 MPa, and elongation (EL) of 8.9 %. The presence of Ti particles within the composite hinders the basal slip of the Mg matrix during plastic deformation, facilitating the early onset of tensile twinning. The Ti particles contribute to grain refinement, inhibit slip deformation, and promote the occurrence of additional twins within the grains. The second phase, Mg41Nd5, is distributed along the powder boundaries, with dislocation tangles observed within the grains. Twin boundary strengthening is identified as the primary factor for the increased YS in the MDC 6Tip/WE43 composite. Additionally, the MDC 6Tip/WE43 composite demonstrates superior thermal conductivity compared to the MDC WE43 alloy, which is attributed to its less pronounced basal texture.

Optimizing microstructure and strength of CMT-wire arc additive manufactured WE43 Mg alloy through a novel active cooling technique

Cold metal transfer (CMT)-Wire arc additive manufacturing (WAAM) has been widely utilized in the production of large Magnesium (Mg) alloy components. However, the thermal cycling and heat input inherent in the CMT-WAAM process can adversely affect the microstructure and properties of Mg-Rare earth (RE) alloys. Currently, there is a lack of effective, low-cost, and easy-to-implement methods to mitigate these issues. In this study, an active cooling technique (ACT) comprising base cooling and bypass cooling was proposed. The ACT facilitates in-situ cooling of CMT-WAAMed WE43 components through uninterrupted water flow in the substrate and bypass plate, offering advantages in cost-effectiveness, safety, and ease of implementation. It was found that the CMT-WAAMed WE43 alloy thin wall component manufactured with the ACT assistance had fewer hard-brittle eutectic phases and finer grains due to the accelerated cooling rate. ACT effectively reduced the heat accumulation and peak temperatures in the component. Furthermore, it inhibited the transformation of the β1 phase to the β phase and suppressed the coarsening of the β1 phase. ACT also improved the ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) of the CMT-WAAMed WE43 component by 11.7 %, 5.8 %, and 72.3 %, respectively. This study provides a novel approach for the microstructure optimization of CMT-WAAMed Mg-RE alloy, which is crucial for the production of high-performance and large-size components in the aerospace industry.

Unveiling mechanical response and deformation mechanism of extruded WE43 magnesium alloy under high-speed impact

To clarify the mechanical behavior and deformation mechanism of rare earth magnesium (Mg) alloy WE43 under extreme service loads, high-speed impact tests under various deformation temperatures and loading paths were conducted using a split Hopkinson pressure bar. The flow stress along extrusion direction (ED) and extrusion radial direction (ERD) decreases apparently with deformation temperature. Compared with conventional Mg alloys, it exhibits a slight anisotropy and an unusual C-shaped characteristic. Cellular dislocation, mechanical twin and fine grain that occur after high-speed impact deformation are insensitive to the loading direction, but strongly dependent on the deformation temperature, especially superimposed with adiabatic temperature rise. As a result, dynamic recrystallization (DRX) occurs even at an ambient temperature of 25 °C. Double twinning and prismatic slip or pyramidal slip are the dominant deformation mechanisms at 25 °C. These twins induce mechanical cutting refinement to form some fine-grained structures, accompanied by a small number of fine grains by twinning induced DRX. In contrast, the deformation at 250 °C is mainly controlled by prismatic slip and pyramidal slip, accompanied by various types of twinning in early deformation stage. Compared with 25 °C, more fine-grained microstructures are formed at 150 and 250 °C through a synergy mechanism of twinning induced mechanical cutting and twinning induced DRX.

Tailoring Deformation Homogeneity of WE43 Alloy through Strain Rate Sensitivity and Back Pressure during Equal Channel Angular Pressing

Equal channel angular pressing (ECAP) of the magnesium alloys at room temperature owing to their limited workability is challenging. Successful ECAP processing of WE43 magnesium faces two main difficulties, heterogeneous distribution of the strain rate and also tensile strain accommodation on the top surface of the workpiece, leading to catastrophic segmentation of the alloy. In this paper, strain rate sensitivity (SRS) was studied to adopt a proper preprocessing of the material before ECAP processing. The SRS exponents, obtained from compression tests, revealed that solution treatment reduced the SRS of the alloy. To mitigate strain accommodation, an ECAP core-sheath configuration was used to induce back pressure for the sake of deformation homogeneity improvement. A combination of experimental processing and 3D finite element method simulations was applied to the solution-treated WE43 alloy with different core sizes and sheath materials. By finding the optimized core sizes and sheath materials with higher strengths, the differences in microhardness and equivalent plastic strain were reduced. Besides, the adequate magnitude of back pressure and the imposed fully compressive stress prevent fragmentation of the WE43 core during ECAP. After stepwise modifications, the plastic strain inhomogeneity index decreased from 1.340 to 0.671.