Cast Magnesium Alloy Research Articles

Effect of Hot-Dipped Tin Coating Treatment on Metallurgical Bonds Between AZ91D and Cu by Composite Casting

Mg-Cu bimetallic materials have been widely studied because of their low density, good electrical conductivity, and excellent hydrogen storage properties. However, the interface bonding strength of Mg/Cu is low. In this study, we examined the effect of hot-dip tin coating (HDTC) with copper (Cu) on the interfacial metallurgical bonds between AZ91D Magnesium (Mg) alloy and Cu composite casting. A transition layer composed of Mg2Cu and MgCu2 intermetallic compounds (IMCs) formed at the interface of the AZ91D/HDTC-Cu composite casting. However, the transition layer was about 1 μm at the AZ91D/Cu interface, mainly comprising Mg(Al, Cu)2 IMC. Both the AZ91D/Cu and AZ91D/HDTC-Cu interfaces exhibited many labyrinthine Mg(Al, Cu)2 IMCs and layer-like Mg2(Al, Cu) IMCs. Moreover, the interfacial shear strength of the AZ91D/Cu was changed from 12.6 MPa to 52.4 MPa due to the solid solution of Sn atom and the precipitation of Mg2Sn IMC at the interface after HDTC treatment. Meanwhile, the shear fracture surfaces are characterized by brittle fractures.

A strain integrated gas infusion process (SIGI) for magnesium alloy castings

This study presents a Strain Integrated Gas Infusion Process (SIGI) to manufacture high-performance cast AZ91 magnesium alloys without the addition of secondary alloying elements/reinforcements or secondary processing. The current SIGI process involves a combination of agitation and localized rapid heat extraction via strain integration and high-energy gas infiltration. The SIGI casting process has been compared systematically with conventional techniques. The critical process parameters, including hole diameter, bubble diameter, and flow rate, have been optimized through numerical calculations, simulations, extensive experiments, and comprehensive analysis. The study also focused on investigating the effect of gas bubbles on the molten metal and established the mechanisms involved in improved solidification. Gas infusion combined with strain integration impacts the solidification process, ensuring uniform alloying element distribution and reducing segregation and microporosity. This manufacturing strategy eliminates casting defects such as segregation and microporosity, resulting in a non-dendritic homogeneous microstructure. The significant refinement in morphologies of both primary (α-Mg dendrites) and secondary (β-Mg17Al12 phase) phases highlights the success of the current SIGI process. Compared to the conventional casting processes, a remarkable improvement in strength-ductility synergy is achieved in the current SIGI process. The scientific know-how and efficiency of the current SIGI process are established and discussed in detail, providing a promising solution to address the existing challenges encountered in magnesium alloy billet castings. The SIGI process improves the mechanical properties and corrosion resistance of billet-cast magnesium alloys. The SIGI process is suitable for the billet casting, offering significantly improved properties but faces limitations in complex mold casting applications. The billets casted by SIGI process can be used as a high-quality precursors for downstream processes to create industrial components.

Effect of Microporosity and Precipitation Phases on the Quality Index of AZ Series Magnesium Alloy Castings with Varying Grain Sizes

Effect of Microporosity and Precipitation Phases on the Quality Index of AZ Series Magnesium Alloy Castings with Varying Grain Sizes

Magnesium alloys in the automotive industry: Alloying elements and their impact on material performance

This study aims to systematically review and evaluate the application of magnesium (Mg) within the automotive sector, with a focus on enhancing fuel efficiency and supporting environmental sustainability. The review emphasizes the latest advancements in cast magnesium alloys, wrought magnesium alloys, and functional magnesium materials, including the development of novel Mg-based materials. The environmental impact of utilizing magnesium in automotive components is also critically analyzed. Recent innovations, particularly in the fields of nanocomposites and alloying, have significantly enhanced the mechanical properties of magnesium alloys, such as increased strength and improved grain refinement, making them suitable for high-temperature applications. The findings suggest that the competitive pricing and enhanced properties of magnesium and its alloys are key drivers for their widespread adoption in automotive manufacturing. The paper provides a detailed discussion on the current trends in magnesium alloy applications, with particular focus on the role of alloying elements and strategies to address associated challenges. This comprehensive review outlines the recent technological advancements in magnesium materials and their relevance to modern engineering applications in the automotive industry.

Investment casting of porous Mg-alloy networks biomechanically tuned for bone implant applications

Manufacturing technology has been refined and described for the fabrication of honeycomb-based bioresorbable networks for temporal bone replacement applications. Two novel techniques, digital light processing and investment casting, were utilized to produce customized, shape-optimized cellular constructs with additional orifices promoting tissue ingrowth during osteo-regeneration. For this purpose, a conventional magnesium casting alloy (AZ91) was chosen. Numerical simulations were conducted to predict the compressive behavior of the proposed biodegradable lightweight scaffolds. Spatial castings were adjusted to possess mechanical properties comparable to the ones of cortical or trabecular bones. Two kinds of protective coatings (plasma electrolytic oxidation and organic ones based on natural polyphenols from tea extract) were deposited and characterized. They can be utilized to control the degradation rate during exploitation to achieve a predictable implant lifespan. The elaborated layers aim to mitigate the rapid corrosion of magnesium substrates by prolonging their bioresorption time and thus expanding their applicability in osseointegration. To evaluate this assumption, immersion tests in phosphate-buffered saline were performed, showing better chemical resistance of PEO coating and as-cast sample (for both mass gain by below 1%), and visible increase in mass of sample coated with organic coating (increase by almost 5%). Compressive strength results from numerical approach were further validated by experimental compression tests, showing that PEO coating deteriorated compressive strength by almost 3%, and organic coating improved it by over 9%. Results achieved in numerical approach were better than expected for stiffer sample, and slightly lower for the one with bigger pores.

Research progress on semi-continuous casting of magnesium alloys under external field

Research progress on semi-continuous casting of magnesium alloys under external field

Achieving significant grain refinement efficiency in Mg-Al alloys via a GNP@MgO composite refiner

Master alloys containing Zirconium (Zr) serve as effective grain refiners in most commercial cast magnesium (Mg) alloys. However, their efficacy is diminished in Mg–Al series alloys due to the formation of Al–Zr compounds. In this work, a novel Mg-GNP@MgO master alloy was prepared utilizing the in-situ reaction between CO2 and Mg. The grain refinement efficiency of this composite inoculation on Mg–9Al alloys was systematically investigated using SEM-EBSD, HRTEM observations, Density Functional Theory (DFT), and Sharp Interface Model (SIM) calculations. The findings suggest that the composite grain refiner (GNP@MgO) exerted a notable refining influence on Mg–9Al alloy. Through the conventional casting process, the average grain size was refined to approximately 13 μm upon the addition of 3 vol% GNP@MgO, achieving a grain refinement efficiency of 90 %. The enhanced refining efficiency arises from the synergistic control over the nucleation and growth processes of α-Mg grains, facilitated by GNP@MgO particles. This process includes improved heterogeneous nucleation, triggered by the newly formed Al4C3 phases through the interaction between GNPs and Al element, followed by the limited expansion of α-Mg grains induced by the nano-sized MgO particles. The MgO particles predominantly gather around grain boundaries to establish stable nano-coating layers, thereby exerting a substantial Zener pinning effect. The pinning role played by the MgO nanoparticles was also verified by a sharp interface model. The findings in this work not only carve out a new avenue for the grain refinement of cast Mg–Al alloys but also inspire fresh perspectives for the development of novel grain refiners.

Kinetics of Aging and Changes in the Mechanical Properties of Mg – Y – Nd – Gd – Zn – Zr Cast Magnesium Alloy During Overburning

Kinetics of Aging and Changes in the Mechanical Properties of Mg – Y – Nd – Gd – Zn – Zr Cast Magnesium Alloy During Overburning

Effect of Cold Metal Transfer Welding Repair Parameters on the Forming for the Repair of Surface Defects of Cast Magnesium Alloy

Effect of Cold Metal Transfer Welding Repair Parameters on the Forming for the Repair of Surface Defects of Cast Magnesium Alloy

Energy Required for Erosive Wear of Cermet Coatings Sprayed Using the High-Velocity Oxygen Fuel Method on a Magnesium Alloy Substrate

The manuscript analyzes the impact of the HVOF (high-velocity oxygen fuel) coating spraying technology on a substrate made of a light and high-specific-strength magnesium casting alloy from the AZ31 series. Among others, the following were examined: the influence of the spraying distance of coatings using commercial cermet powders (WC–Co, WC–Co–Cr, and WC–Cr3C2–Ni) on their resistance to erosive wear. It is worth emphasizing the energy savings resulting from the possibility of spraying on the surfaces of existing machine parts to protect or regenerate them. Energy savings result from the possibility of recycling the substrate material (AZ31), as well as from extending the functionality of an existing element without the need to dispose of it and the energy-intensive production of a new component. Tests have shown that the best resistance to the destructive effects of erodent in the form of hard corundum particles is characterized by a WC–Co–Cr coating sprayed at a distance of 320 mm.

Fabrication of nano SiC and BF-bonded magnesium alloy (AZ80) hybrid nanocomposite via liquid state stir casting process: characteristics study

ABSTRACT Concerning various materials in the engineering domain, magnesium alloy-based composites are found to have specific properties. They are prepared with ceramic particles via a liquid stirring process, and oxidation results in porousness. Due to this, this research aims to develop cast magnesium alloy (AZ80), nanocomposite and hybrid nanocomposites via a liquid state stir casting process with an argon atmosphere. It contains 0, 2, 4 and 6 wt% of silicon carbide nanoparticles (SiC) and 6 wt% SiC with 3, 6 and 9 wt% of basalt fibre. The developed cast AZ80 alloy, nano and hybrid nanocomposites are subjected to physical, mechanical and wear behaviour studies, and their results are compared. The composite contained 6 wt% SiC, and 9 wt% BF showed low porosity (1.03%), superior tensile strength (359 ± 7 MPa), elastic modulus (23044.58 ± 230 MPa), strain (2.114 ± 0.01 mm), hardness (121 ± 1.02 HV), coefficient of friction (0.421 ± 0.02) and low impact strength (18.25 ± 0.34 J/mm2) and volumetric wear rate (5.36 ± 0.4 mm3/m) compared to others.

Corrosion resistance of squeeze cast magnesium alloy AM60-based hybrid nanocomposite coated with plasma electrolytic oxidation

ABSTRACT Plasma electrolytic oxidation (PEO) coating with NaAlO2 and KOH electrolytes was applied on the surfaces of as-cast AM60 (PEO-AM60), 7 vol.% Al2O3 fibres/AM60 (PEO-7FC) and 7 vol.% Al2O3 fibres + 3 vol.% Al2O3 nano-sized particles/AM60 (PEO-MHNC-7F3NP) to improve their corrosion resistance. The SEM and EDS analyses indicated that the PEO coating process formed a porous and dense layer on the substrate surface, as well as MgAl2O4 was the major concentration of the coating. The thickness of PEO coating on the 7FC and MHNC-7F3NP composites was slightly less than the coating on the AM60. The electrochemical corrosion tests were carried out in 3.5% NaCl aqueous solution at room temperature for investigating the corrosion behaviour of the as-cast AM60 and the composites after applying the PEO coating. The PEO coating increased the corrosion resistance of the AM60 alloy and the 7FC and MHNC-7F3NP composites to 342.81, 301.73 and 290.44 from 4.07, 2.08 and 1.88 kΩ∙cm2. By comparing the corrosion test results of the coated AM60 and the composites with those of the uncoated counterparts, it was found that the PEO coating significantly improved the corrosion resistance by up to 154 times. The addition of nano-sized particles barely increased the corrosion rate of the composite.

Recent progress on cast magnesium alloy and components

Recent progress on cast magnesium alloy and components

Effect of pulse gas tungsten arc welding on the metallurgical characteristics & microstructural evolution in AZ31B magnesium alloy welds

This work assessed the effects of frequency & the pulse duration ratios on the weldability & structure-property relationships for the magnesium alloy AZ31B. In addition, AC/DC pulse welding with different pulse duration ratios was explored, to assess controlled repair welding on magnesium alloy castings. Complete penetration welds can be produced with conventional GTA welding using a heat input of ∼500 J/mm without the need for an active flux. However, the weld metal has a coarse grain structure and micro cracks, suggesting the need for an even better control of heat input for achieving defect free welds. Pulse GTA welding with at lower frequencies give relatively deeper penetration joints at different pulse duration ratios (1:1, 1:2 and 1:4). However, the full penetration welds are possible only with pulse duration ratio of 1:1. All the welds produced under pulsed GTA welding conditions were defect free. The grain sizes of the weld metals were much finer than for conventional GTA welding conditions and have a higher hardness compared to conventional GTA weld & also the parent alloy. Use of AC/DC mix for pulse welding, with the peak current being AC and the base current as DC, yields shallow penetration welds with no defects. The resultant weld metal microstructures are of finer grain size, and with finely distributed β-phase particles. This welding technique can be exploited for repair welding of magnesium alloy castings that have near-surface defects.

A novel damage mechanics and XGBoost based approach for HCF life prediction of cast magnesium alloy considering internal defect characteristics

In this study, a novel method integrating machine learning with damage mechanics is proposed for predicting the high cycle fatigue life of ZM6 with internal defects. First, the characterization model of the effects of internal defects is presented, and the relationship between the stress concentration factor and the parameters of the ellipsoidal void is established. After that, the internal defect hazard factor is proposed to reflect the influence of ellipsoidal void on the fatigue behavior, and the fatigue damage model considering the effects of internal defects is derived. Second, the fatigue tests of ZM6 are carried out on smooth specimens with different stress ratios, and the 3D morphology of internal defects in standard test specimens is acquired by utilizing X-ray scans. A calibration method for material parameters based on the particle swarm optimization (PSO) algorithm is proposed. Based on the validated new damage mechanics model, a dataset is then generated to train the eXtreme Gradient Boosting (XGBoost) machine learning model. Lastly, the high cycle fatigue life of ZM6 is predicted with the given stresses, stress ratios, and hazardous defect coefficients, and a high prediction accuracy is achieved. The effects of the number of training samples and hyper-parameters on prediction performance are further investigated.

Material Selection for Differential Gearbox under Torque Conditions: A Simulation-Based Study

Abstract: This research paper conducts an in-depth exploration into the structural behaviors of three distinct materials—Cast Iron, Copper Alloy, and Magnesium Alloy—within the framework of a differential gearbox under varying torque loads. Employing finite element analysis through ANSYS, the investigation systematically scrutinizes critical parameters such as total deformations, equivalent stress (von Mises stress), and shear stress. The primary aim is to offer insights that guide material selection strategies and enhance the optimization of design processes in automotive applications. The results illuminate nuanced material responses when exposed to torque conditions, presenting implications for real-world gear assembly scenarios. This study significantly contributes to the evolving knowledge base in automotive engineering, providing a foundation for wellinformed decision-making in material selection and design optimization for differential gearboxes.

Study of Crack Growth Behaviour in a Cast Magnesium Alloy

This paper presents the study of the effects of the Magnesium Silicates on the crack initiation. The most fascinating part of this study is the propagation of the crack in magnesium alloys under a static load. Detailed fractography of the fracture surfaces of the cast Magnesium alloy revealed that the crack was initiated from silicon inclusion that had probably originated from the sand mould and had been washed throughout the casting on the advancing metal stream.The examination of the fracture surface shows the crack propagated to failure in brittle mode.Recommendations to reduce the risk casting defects and flaws are proposed in this study.

Microstructure and properties of the GEWZ522K casting magnesium alloy based on the Mg–Gd–Nd–Y–Zn–Zr system

The article discusses the solidification and phase composition of the (wt.%) Mg–4.8Gd–2.1Nd–1.6Y–0.4Zn–0.6Zr (GEWZ522K) casting alloy. It is demonstrated that in the as-cast state, the alloy structure comprises primary zirconium particles, dendrites of the magnesium solid solution (αMg), and eutectic intermetallic phases located between dendritic branches. Following solution heat treatment at t = 530±5 °C, the alloy transitions into a single-phase state and can be significantly strengthened through artificial aging after quenching. It is recommended to apply alloy aging at t = 250 °C for 8–10 h or at t = 200 °C for 15–18 h. This approach leads to the maximum strengthening of the alloy, with the best mechanical properties achieved for the alloy aged at t = 250 °C. Regardless of the aging method used, the ultimate tensile strength (UTS) of the samples surpasses 300 MPa, which significantly exceeds that of commercial casting alloys according to GOST 2856-79. The measured corrosion rate for the GEWZ522K alloy is 7.5±0.4 mm/year, that slightly higher than that for the less alloyed commercial alloy ML10 (approximately 2.5 mm/year) tested under similar conditions. Furthermore, the alloy was subjected to tests for ignition resistance when in contact with air. It was observed that with continuous airflow over the specimen’s surface, ignition centers appear at t = 625 °C due to the breakdown of the oxide film, causing the alloy to nearly completely melt. Therefore, the GEWZ522K alloy can be employed as a high-strength casting alloy. However, during the operation of cast parts, particular attention must be paid to safeguarding the surface of these parts against corrosion.

Electrochemical corrosion of stir cast and heat-treated magnesium alloy EV31A in different electrolytes: Analysis via X-ray photoelectron spectroscopy

The study aims to determine the chemical state of elements in EV31A after electrochemically corroded in four different electrolytic solutions. EV31A, a magnesium alloy containing rare earth elements, was manufactured via stir-casting and heat-treated based on T4 and T6 conditions. Electrochemical corrosion of the as-cast, T4, and T6 EV31A were carried out in 0.6 M NaCl, 0.05 M H2SO4, 0.1 M HNO3, and 0.1 M HF solutions. In addition, the X-ray photoelectron spectroscopy (XPS) examination was performed on the corroded surface of EV31A. During the XPS analysis, the elements such as Magnesium (Mg), Neodymium (Nd), Gadolinium (Gd), Zinc (Zn), Zirconium (Zr), chlorine (Cl), sulphur (S), nitrite (N), fluorine (F), and oxygen (O) were studied, and only the peaks of Mg, O, Nd, and Gd were detected on the surface of corroded alloy. In all test settings, the corrosion resistance of the as-cast alloy is better than that of the heat-treated alloy. Even though the corrosion resistance of the as-cast alloy is high, its corrosion rate of EV31A in H2SO4 and HNO3 is very high. The corrosion resistance of as-cast EV31A in NaCl and HF mainly results from the formation of Nd2O3 and electronegative fluorine, respectively, as determined by XPS.

Low-cost high-strength Mg–7Zn-xAl-0.3Mn (x=1, 3, 5) cast magnesium alloys via grain boundary strengthening and precipitation strengthening

Obtaining a highly synergistic strength and elongation in cast magnesium (Mg) alloys at low cost is a chronic problem. A series of low-cost and high strength cast Mg–7Zn-xAl-0.3Mn (x = 1, 3, 5) alloys (labeled as ZAM710, ZAM730, and ZAM750 alloys, respectively) were designed based on the phase diagram simulation and prepared successfully by electric resistance furnace. The present results showed that the as-cast ZAM710 alloy was composed of α-Mg, MgZn, AlMn, and Al8Mn5 phases. The MgZn phase disappeared and the Mg32(Al, Zn)49 phase formed as the Al content increased to more than 3 wt%. In addition, with the increase of Al content, the volume fraction of the second phase increased and the grain was refined. The microstructures and mechanical properties of these alloys were improved after heat treatment. Among them, the transmission electron microscopy analysis showed that there were a large number of nanometer precipitation strengthening phases in the aged ZAM750 alloy. One was a rod-shaped Mg4Zn7 phase and the other was a disk-shaped MgZn2 phase. The comprehensive mechanical properties of the ZAM750 alloy were most outstanding, and the tensile strength, yield strength, and elongation were 309.4 MPa, 202.0 MPa, and 6.1%, respectively. The strengthening mechanism of the ZAM750 alloy mainly included grain boundary strengthening and precipitation strengthening, and the contribution values to the yield strength of the ZAM750 alloy were 95.8 MPa and 75.7 MPa, respectively. This work can provide some guidance and new design ideas for the development of low-cost and high-strength cast Mg alloys.