Fluid Solution Research Articles

Global existence of non-Newtonian incompressible fluid in half space with nonhomogeneous initial-boundary data

In this study, we investigate the global existence of weak solutions of non-Newtonian incompressible fluids governed by (1.1). When u0∈Ḃp,qα−2p(R+n)∩Ḃn+22,n+221−4n+2(R+n)∩Ḃp,11+np(R+n) is given, we will find the weak solutions for the Eq. (1.1) in the function space Cb[0,∞;Ḃp,qα−2p(R+n)∩Cb(0,∞;Ḃn+221−4n+2(R+n))∩L∞(0,∞;Ẇ∞1(R+n)), n+2<p<∞,1≤q≤∞,1+n+2p<α<2. We show the existence of weak solutions in the anisotropic Besov spaces Ḃp,qα,α2(R+n×(0,∞)) (see Theorem 1.2) and we show the embedding Ḃp,qα,α2R+n×(0,∞)⊂Cb[0,∞;Ḃp,qα−2p(R+n) (see Lemma 2.8). For the global existence of solutions, we assume that the extra stress tensor S is represented by S(A)=F(A)A, where F satisfies the assumption (A). Note that S1, S2 and S3 introduced in (1.2) satisfy our assumptions.

Most general isotropic charged fluid solution for Buchdahl model in ℱ(𝒬) gravity

In this work, we investigated a most general isotropic charged fluid solution for the Buchdahl model via a two-step method in ℱ(𝒬)-gravity framework for the first time. In this context, a linear function of the form ℱ(𝒬) = ζ 1 𝒬 + ζ 2 and a particular transformation is used to solve the Einstein-Maxwell Equations (EMEs) employing the Buchdahl ansatz: e Υ(r) = μ(1+λ r 2)/μ+λ r 2, where ζ 1, ζ 2, λ and μ are constant parameters. The Schwarzschild de Sitter (AdS) exterior solution is joined to the interior solution at the boundary to determine the constant parameters. It should be emphasized that, for a given transformation, the Buchdahl ansatz only offers a mathematically feasible solution in the context of electric charge, where pressure and density are maximum at the center and decrease monotonically towards the boundary when 0 < μ < 1. We taken into account the compact star EX01785-248 with M = (1.3±0.2)M ⊙; Radius = 12.02+0.55 -0.55 km for graphical analysis.The physical acceptability of the model in the context of ℱ(𝒬) gravity has been evaluated by looking at the necessary physical properties, including energy conditions, causality condition, hydrostatic equilibrium, pressure-density ratio, etc. Additionally, we predicted the maximum mass limit of different compact objects for various parameter values along with the mass-radius relation. The maximum masses range (1.927 - 2.321) M ⊙ are obtained for our solution. It can be observed that when the coupling parameter ζ 1 for ℱ(𝒬 gravity is smaller, then our solution yields massive stars. The present investigation provides novel insights and realistic implications regarding the formation of compact astrophysical objects.

Solute transport in stochastic discrete fracture-matrix systems: Impact of network structure

Obtaining a comprehensive understanding of solute transport in fractured rocks is crucial for various geoengineering applications, including waste disposal and construction of geo-energy infrastructure. It was realized that solute transport in fractured rocks is controlled by stochastic discrete fracture-matrix systems. However, the impacts and specific uncertainty caused by fracture network structures on solute transport in discrete fracture-matrix systems have yet not been fully understood. In this article, we aim to investigate the influence of fracture network structure on solute transport in stochastic discrete fracture-matrix systems. The fluid flow and solute transport are simulated using a three-dimensional discrete fracture matrix model with considering various values of fracture density and size (i.e., radius). The obtained results reveal that as the fracture density or minimum fracture radius increases, the corresponding fluid flow and solute transport channels increase, and the solute concentration distribution range expands in the matrix. This phenomenon, attributed to the enhanced connectivity of the fracture network, leads to a rise in the effluent solute concentration mean value from 0.422 to 0.704, or from 0.496 to 0.689. Furthermore, when solute transport reached a steady state, the coefficient of variation of effluent concentration decreases with the increasing fracture density or minimum fracture radius in different scenarios, indicating an improvement in the homogeneity of solute transport results. The presented analysis results of solute transport in stochastic discrete fracture-matrix systems can be helpful for uncertainty management in the geological disposal of high-level radioactive waste.

Significance of Cattaneo–Christov heat flux theory and convective heat transport on Maxwell nanofluid flow

AbstractRecently, nanofluids, which are solutions of fluids mixed with suspended nano‐particles, for instance, carbon nanotubes, metals, and metal oxides, have become a favorable alternative to conventional coolants. Caused by their outstanding thermal performance of conductivity, nanofluids are extensively used in battery‐operated drums, thermoelectric producers, and solar power. The suspension of minor solid components in energy dispersion fluids boosts their thermal enactment of conductivity and gives an economical and resourceful method to increase their transfer properties of heat significantly. Furthermore, additions of nanofluids to numerous engineering and mechanical matters, for instance, electrical kit conserving, heat exchangers, and chemical progressions, are uses of nanofluid. Here, the purpose of this work is to elaborate on the flow of Maxwell nanofluid by considering chemical reactions and heat sink/source. The mathematical structure is established with the presence of Brownian movement and thermophoresis effects. The remarkable aspects of non‐Fourier heat flux are also considered with the transport phenomenon of convective conditions. The similarity alterations change the partial differential equations (PDEs) into ordinary differential equations (ODEs). The obtained expressions of ODEs are solved numerically via the bvp4c approach. The graphical sketches display the declining behavior of Maxwell factor for velocity; however, the same impacts are examined for Brownian and thermophoresis factors. Furthermore, Schmidt and chemical reaction factors decline the concentration field of Maxwell nanofluid.

Applied Electric Field Effects on Diffusivity and Electrical Double-Layer Thickness.

This study utilizes molecular dynamics (MD) simulations and continuum frameworks to explore electroosmotic flow (EOF) in nanoconfined aqueous electrolytes, offering a promising alternative to conventional micro-/nanofluidic systems. Although osmotic behavior in these environments is deeply linked to local fluid properties and interfacial dynamics between the fluid and electrolyte solutions, achieving a complete molecular-level understanding has remained challenging. The findings establish a linear relationship between electric field strength and fluid velocity, uncovering two distinct transport regimes separated by a critical threshold, with a markedly intensified flow in the second regime. It is demonstrated that rising electric field strengths significantly enhance water diffusion coefficients, supported by a detailed analysis of fluid hydration structures, the potential of mean force (PMF), and local stress tensors. Due to the applied electric field strength, the motion of ions and water accelerates, leading to the redistribution of ions and intensification of electrostatic forces. This expands the thickness of the electric double layer (EDL) and amplifies fluid diffusivity, thereby enhancing nanoscale fluid activity. These insights enhance the molecular-level understanding of EOF and define the stability of flow regimes, providing valuable guidelines for advancing nanofluidic technologies, such as drug delivery systems and lab-on-a-chip devices.

A formulation for fluid–structure interaction problems with immersed flexible solids: Application to splitters subjected to flow past cylinders with different cross-sections

In the finite element method framework, a fluid–structure formulation is developed by coupling an Eulerian fixed-mesh fluid approach with a Lagrangian deforming-mesh description for a flexible solid. The coupled formulation is solved using a staggered scheme during time. For the fluid solution stage, the solid walls are considered as a time-variable internal boundary. The velocity and pressure fields are obtained by solving the weak form of the fluid dynamic equations in which the solid velocity is imposed on the internal boundary via a penalization term. For the solid solution stage, the displacement field is obtained by solving the discrete solid dynamic equations which consider traction forces computed by integrating pressures and viscous stresses on the nodes belonging to the solid walls. This novel technique is firstly applied to analyze a flexible splitter under the shedding of a flow past square cylinder due to this problem is considered as a benchmark in the literature. The present solutions agree with those computed using body-fitted techniques, thus validating the proposal. Secondly, flexible splitter motions under the shedding of flow past cylinders with different cross-sections and splitter lengths are comprehensively studied. Overall, the computed results confirmed that the hydrodynamic coefficients on the cylinders were reduced because of the presence of the splitter.

Synthesis and characterization of hydroxyapatite coatings with superior performance for corrosion protection of Ti-6Al-4V alloy in simulated bodily fluid

Hydroxyapatite nanoparticles (HAP-NPs) were synthesized using a microemulsion (cetyltrimethylammonium bromide (CTAB) and dimethyl sulfoxide (DMSO) as surfactants) method. The influence of the optimum ratios of CTAB concentrations as surfactants in the microemulsion on HAP morphology was investigated. After dispersing the HAP powders, a high-speed spin coating process at 2500 RPM was employed to produce HAP coatings on the Ti-6Al-4V alloy. The HAP-NP properties were characterized using techniques such as XRD, FTIR, FESEM, and AFM. Studies utilizing electrochemical impedance spectroscopy (EIS) in a simulated body fluid (SBF) solution. The corrosion resistance of coated samples compared to bare substrate increased from 67 to 853.34 kΩ cm2.

Mechanical properties and corrosion behavior of biodegradable Mg-Cu alloys

Mechanical properties and in vitro corrosion behavior of Mg-Cu alloys in the simulated body fluid solution were investigated. Copper addition led to grain refinement and formation of α–Mg/Mg2Cu eutectics, resulting in the best combination of mechanical properties for the as-cast Mg-0.5Cu alloy, for which the values of the yield stress, ultimate tensile strength, total elongation, and tensile toughness were obtained as 71 MPa, 164 MPa, 5.8%, and 7.5 MJ/m3, respectively. Hot deformation by extrusion led to fine grain sizes via dynamic recrystallization and breaking up the eutectics. Accordingly, the extruded Mg-0.1Cu alloy showed tensile toughness of ∼30 MJ/m3 and good corrosion resistance; while Mg-1.2Cu alloy with a distinct protective surface layer was also considered as a viable alternative for biomedical applications.

The retention factors and partial molar volumes of cycloartenyl ferulate at infinite dilution in supercritical carbon dioxide: Measurements and correlation

The retention factors and infinite dilution partial molar volumes of a solute in supercritical fluid are crucial for understanding solute–solvent interactions, analyzing pressure effects on chemical reactions, and optimizing industrial processes. Despite their importance, there is a notable scarcity of available data on retention factors and infinite dilution partial molar volumes in supercritical fluid systems. This study presents the first experimental data on the retention factors and partial molar volumes of cycloartenyl ferulate at infinite dilution in supercritical carbon dioxide. The retention factors were measured across temperatures ranging from 308.15 to 353.15 K and pressures of 8.20 to 31.03 MPa using supercritical fluid chromatography. The infinite dilution partial molar volumes were determined by taking the partial derivative of the retention factors with respect to the density of carbon dioxide. The obtained infinite dilution partial molar volumes range from −1.64 × 10−2 to 4.10 × 10−4 m3/mol, with large negative values observed near the critical point of carbon dioxide, indicating strong solvent–solute interactions. In this study, a new correlation model successfully predicts the experimental infinite dilution partial molar volumes with an average absolute relative deviation of 2.3 % over 86 data points.

(Invited) Exciton Dynamics in Triplet Fusion of Diphenylanthracene in Fluid Solution and Crystalline Solid

Triplet fusion (TF) has recently attracted attention because of its great potential of various applications. Since high reaction efficiency of TF is demanded in any applications, it is necessary to clarify the mechanism of triplet exciton dynamics that is an important elementary process to enhance the TF efficiency. Therefore, in this paper, we study the triplet exciton dynamics of 9,10-diphenylanthracene (DPA), which shows the TF-based fluorescence, in a solvent of tetraethylene glycol dimethyl ether and in polycrystal of DPA, in combination with the triplet sensitization using platinum octaethylporphyrin. The observed emission kinetics and their magnetoluminescence effect indicate that the rotational and the multitrapping diffusions of the triplet exciton play an inherent role respectively in the fluid solution and in the polycrystalline solid.

FSGe: A fast and strongly-coupled 3D fluid–solid-growth interaction method

Equilibrated fluid–solid-growth (FSGe) is a fast, open source, three-dimensional (3D) computational platform for simulating interactions between instantaneous hemodynamics and long-term vessel wall adaptation through mechanobiologically equilibrated growth and remodeling (G&R). Such models can capture evolving geometry, composition, and material properties in health and disease and following clinical interventions. In traditional G&R models, this feedback is modeled through highly simplified fluid solutions, neglecting local variations in blood pressure and wall shear stress (WSS). FSGe overcomes these inherent limitations by strongly coupling the 3D Navier–Stokes equations for blood flow with a 3D equilibrated constrained mixture model (CMMe) for vascular tissue G&R. CMMe allows one to predict long-term evolved mechanobiological equilibria from an original homeostatic state at a computational cost equivalent to that of a standard hyperelastic material model. In illustrative computational examples, we focus on the development of a stable aortic aneurysm in a mouse model to highlight key differences in growth patterns between FSGe and solid-only G&R models. We show that FSGe is especially important in blood vessels with asymmetric stimuli. Simulation results reveal greater local variation in fluid-derived WSS than in intramural stress (IMS). Thus, differences between FSGe and G&R models became more pronounced with the growing influence of WSS relative to pressure. Future applications in highly localized disease processes, such as for lesion formation in atherosclerosis, can now include spatial and temporal variations of WSS.

Exact solutions of non-singularized MHD Casson fluid with ramped conditions: A comparative study

The study of magnetohydrodynamic (MHD) fluids has significant implications across various scientific disciplines, particularly in understanding complex phenomena in astrophysics, engineering, and geophysics. The Casson fluid model stands as a crucial tool for describing non-Newtonian behaviors observed in certain fluid systems. The current work shows an analytical analysis to determine the ramped effect on the fractionalized MHD Casson fluid over an vertical plate. Fractional partial differential equations are used to formulate the problem along with initial and boundary conditions. The governing equations are transformed into the dimensionless form and developed fractional models like Caputo-Fabrizio and Atangana-Baleanu Derivative. We used the Laplace transform technique to find the closed form solution of the dimensionless governing equation analytically. MATHCAD software is being used for numerical computations and the physical attributes of material and fractional parameters are discussed. To analyze their behavior clearly, two-dimensional graphical results are plotted for velocity profile and temperature as well. It has been concluded that the fluid’s velocity are reduced for larger values of the fractional parameter and Prandtl number and is maximum for small values of both parameters.

Solute transport characteristics of columnar volumetric contraction networks with mega column structure and aperture variability

Numerical simulations explore for the first time the role of mega columns and aperture variability on particle transport through mature volumetric contraction networks as informed by a unique synthesis of network propagation and maturity. Columnar fracture patterns are generated by updating a series of Voronoi centers to the midpoint of a generated polygon over many iterations, creating 250 network realizations. A DFN simulator solves for fluid flow and tracks conservative particle trajectories within each network. Dominant fracture attributes impacting fluid flow and solute transport in volumetric contraction networks are fracture orientation, density, and aperture/transmissivity. Ensemble plume snapshots generated by networks with equal fracture transmissivity define a baseline-level of dispersion that is solely attributed to network structure and connectivity. Longitudinal and transverse dispersion increase and the center of plume mass becomes delayed relative to the baseline case when fracture transmissivity is varied according to a lognormal distribution. The incorporation of highly-transmissive, large-aperture mega column fractures leads to plume snapshots with a more pronounced leading edge and an order of magnitude faster average breakthrough times. The breakthrough curves contain three peaks reflecting contrasting transport pathways in which particles are: (i) initially placed in mega column fractures and remain in these features until exiting the model domain, (ii) initially placed into small column fractures, incur additional time to migrate and enter a mega column fracture, and remain within those mega columns, and (iii) initially placed in small column fractures and remain in these fractures. Incorporating variability in fracture transmissivity for both small column and mega column fractures disrupts the binary distinction between small column and mega column fracture velocities and leads to dispersed breakthroughs over long time scales with a single peak. These results demonstrate that preferential flow paths emerge in volumetric contraction networks due to contracts in fracture transmissivity, not fracture connectivity as observed in tectonic networks.

Multifunctional Biocomposites: Synthesis, Characterization, and Prospects for Regenerative Medicine and Controlled Drug Delivery.

This article presents a new method for preparing multifunctional composite biomaterials with applications in advanced biomedical fields. The biomaterials consist of dicalcium phosphate (DCPD) and bioactive silicate glasses (SiO2/Na2O and SiO2/K2O), containing the antibiotic streptomycin sulfate. Materials were deeply characterized by X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy, and zeta potential analysis, UV-visible spectrophotometry, and ion-exchange measurement were applied in a simulating body fluid (SBF) solution. The main results include an in situ chemical transformation of dicalcium phosphate into an apatitic phase under the influence of silicate solutions and the incorporation of the antibiotic. The zeta potential showed a decrease in surface charge from ζ = -24.6 mV to ζ = -16.5 mV. In addition, a controlled and prolonged release of antibiotics was observed over a period of 37 days, with a released concentration of up to 755 ppm. Toxicity tests in mice demonstrated good tolerance of the biomaterials, with no significant adverse effects. Moreover, these biomaterials have shown potent antibacterial activity against various bacterial strains, including Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, suggesting their potential use in tissue engineering, drug delivery, and orthopedic and dental implants. By integrating the antibiotic into the biomaterial composites, we achieved controlled release and prolonged antibacterial efficacy. This research contributes to advancing biomaterials by exploring innovative synthetic routes and showcasing their promise in regenerative medicine and controlled drug delivery.

The impact of diffusiophoresis on hydrodynamic dispersion and filtration in porous media

It is known that the dispersion of colloidal particles in porous media is determined by medium structure, pore-scale flow variability and diffusion. However, much less is known about how diffusiophoresis, that is, the motion of colloidal particles along salt gradients, impacts large-scale particle dispersion in porous media. To shed light on this question, we perform detailed pore-scale simulations of fluid flow, solute transport and diffusiophoretic particle transport in a two-dimensional hyper-uniform porous medium. Particles and solute are initially uniformly distributed throughout the medium. The medium is flushed at constant flow rate, and particle breakthrough curves are recorded at the outlet to assess the macroscopic effects of diffusiophoresis. Particle breakthrough curves show non-Fickian behaviour manifested by strong tailing that is controlled by the diffusiophoretic mobility. Although diffusiophoresis is a short-time, microscopic phenomenon owing to the fast attenuation of salt gradients, it governs macroscopic colloid dispersion through the partitioning of particles into transmitting and dead-end pores. We quantify these behaviours by an upscaled analytical model that describes both the retention and release of colloids in dead-end pores and the observed long-time tailings. Our results suggest that diffusiophoresis is an efficient tool to control particle dispersion and filtration through porous media.

Physically viable and stable charged perfect fluid solution within [formula omitted] gravity

In this work, we investigate the physical behavior and stability of compact stars in F(Q) gravity. We employ the Buchdahl metric to examine the dynamics of a relativistic, newly charged, isotropic fluid model. The interplay between gravity and electromagnetism is included in the analysis of the system by taking into account the charged state of the fluid, providing insights into how charged fluids behave in gravitational theories. The exterior solution under Schwarzschild–de Sitter (dS) spacetime is linked to the interior solution at the boundary to identify the constants. It is important to note that the Buchdahl ansatz provides a mathematically viable solution for a given transformation in the context of electric charge when pressure and density are maximum in the center and monotonically fall towards the boundary. We have taken into account the compact star Her X-1 with M=(0.85±0.15)M⊙; Radius =13.26−1.08+1.08 km for graphical analysis. In the context of F(Q), the physical acceptability of the model has been examined by looking at the required physical attributes, such as energy conditions, causality, hydrostatic equilibrium, pressure–density ratio, etc. that are satisfied throughout the stellar configuration. It is concluded that the present approach allows a suitable modeling of astrophysical compact objects in F(Q) gravity.

Anisotropic extensions of isotropic Finch–Skea metric in the charged modified gravity

In this study, we explore the Finch–Skea perfect fluid solution and extend its domain to three distinct anisotropic interior models within the framework of the f(R,T) theory, incorporating the influence of an electromagnetic field. We assume a static spherical spacetime initially coupled with an isotropic matter distribution. We then introduce a Lagrangian corresponding to an additional gravitating source, taking into account its role in inducing pressure anisotropy within the original fluid source. By deriving the field equations for the combined matter setup, we applied a radial component transformation, which yielded two distinct systems of equations. In addition, we consider a charged exterior spacetime to determine the three constants associated with the Finch–Skea solution at the boundary. Our findings suggest that under certain parametric choices, all three resulting models exhibited physical relevance within this modified theory.

Modified Bentonite As a Dissolve-Extrusion Composite and Its Modification Mechanism.

In the geological core drilling industry, simple and low-cost drilling fluid formulations are required that are easy to apply and maintain. Currently, drilling fluid systems with simple formulations generally exhibit poor performance and do not satisfy the requirements of complex formations. The application of powder surface modification technology has been extensively investigated in several fields; however, few are the studies focusing on the modification of bentonite. Consequently, in this study, based on the surface modification technology of powders, bentonite is modified using the modifiers ZJ-1 and ZJ-2, giving it the characteristic of "one additive with multiple functions". This allows the construction of a new type of drilling fluid system with a simple formulation (water + modified bentonite), excellent performance, and easy application and maintenance. First, a new composite modification method named the dissolution and extrusion composite modification method was proposed, and the dosage of the modifier and the optimal ratio of each modifier were determined experimentally. Second, orthogonal design experiments were conducted to determine the optimal preparation conditions based on the rheological properties of the drilling fluid, dynamic plastic ratio, and filtration loss. Subsequently, the performance of the modified bentonite drilling fluid was analyzed by comparing it to that of a regular bentonite drilling fluid. Finally, the modification mechanism of bentonite was analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). It was revealed that a total modifier dosage of 2% and a ratio of ZJ-1 to ZJ-2 of 1.5:0.5 afforded a modified bentonite drilling fluid with significantly enhanced performance compared to a regular bentonite drilling fluid. The modified bentonite exhibited a filtration loss of 7.5 mL, funnel viscosity of 51.5 s, static shear force of 2.5 Pa, dynamic shear force of 9.198 Pa, apparent viscosity of 29 mPa·s, and plastic viscosity of 20 mPa·s. The experimental repeatability was good, and the optimal preparation conditions for modified bentonite involved a reaction time of 10 h, a reaction temperature of 100 °C, and a mechanical pressure of 0.5 MPa. Microscopic analysis showed that the modifiers were incorporated into bentonite through intercalation and surface adsorption and that the modified bentonite can form a dense filter cake. Our study provides a new drilling fluid solution for the geological core drilling industry, effectively promoting the advancement of drilling fluid technologies.

Analytical and Computational Modeling of Relaxation Times for Non-Newtonian Fluids

With the availability of efficient and sophisticated finite element analysis (FEA) and computational fluid dynamics (CFD) tools, engineering designs are becoming more software-driven and simulation-based. However, the insights relevant to engineering designs tend to be hidden within massive temporal and spatial data produced with full-fledged three-dimensional simulations. In this paper, we present a preliminary study of the controlled intermittent dispensing of a typical non-Newtonian glue employed in the manufacturing of electric vehicles (EVs). The focus of the study is on the scaling issues derived from different computational and analytical models of interest and importance to the precision control of this non-Newtonian fluid, the lowest dynamic viscosity of which at extremely high shear rates is nearly four million times that of water. More specifically, the abrupt change of the inlet pressure with a constant outlet or ambient pressure and various modeling strategies for transient viscous internal flow with both Newtonian and non-Newtonian fluids are modeled and compared. The analytical and computational results of the developing Newtonian fluid, i.e., water, are derived and computed for validation and verification purposes before the actual applications to the developing non-Newtonian fluid. The concept of a well-established relaxation time before the onset of the steady solution for Newtonian fluids has been validated with both analytical and computational approaches before its expansion and adoption to non-Newtonian fluids with complex rheological behaviors. Other issues attributed to transient operations and precision controls of non-Newtonian fluid delivery involve the pressure pulse and pressure wave propagation within the flexible pipe with compressible or almost incompressible non-Newtonian fluids with a constant pressure at the outlet and a constant mass flow rate or average axial velocity at the inlet, which will be addressed in a separate paper.

Investigating the corrosion behavior of as‐cast Mg‐Zn‐Ca alloys with the same Zn/Ca atomic ratio by in situ observation

AbstractThe alloying contents with the same Zn/Ca atomic ratio of 0.13 on the corrosion behavior of Mg‐Zn‐Ca (ZX) alloys were investigated. The second phases in ZX10, ZX20, ZX30, and ZX51 alloys were identical with a majority of Mg2Ca and very few Ca2Mg6Zn3 and their distribution changed from isolated to continuous state in ZX30 and ZX51. ZX10 had the lowest corrosion rate of 0.55 mm/year after 168 h immersion in simulated body fluid solution due to the smallest number of sites of galvanic corrosion. The corrosion rate of ZX30 alloy was the highest (0.72 mm/year), while though ZX51 alloy had the most Mg2Ca, its corrosion rate was reduced to 0.69 mm/year, resulting from the small size and thin Mg2Ca. In situ microstructure observation demonstrated the high fraction Mg2Ca phase and continuous Mg2Ca with bulky size were the main reason for the fast corrosion rate.