Cu-Mg Alloy Research Articles

Evolution of Properties of High-Strength and High-Mg-Content CuMg Alloys After Being Subjected to Single Operation 50% Deformation in Hot and Cold Upsetting Tests

Since most hot and cold metal-forming processes originate from various casting processes, it is important to test their susceptibility to the deformation of new materials. Cast rods of CuMg alloys with a Mg content of 2, 2.4, 2.8, 3, 3.2, 3.6, and 4 wt.% were obtained in the continuous casting process with pure copper as a reference material in order to obtain information on the material’s ability to withstand 50% deformation. The materials in the as-cast state were subjected to solutioning, cold drawing, and recrystallization. After each process, samples were taken and subjected to upsetting tests with 50% deformation applied in a single operation. Additionally, materials in the as-cast state were subjected to upsetting tests at 700 °C. The hardness and electrical conductivity of each sample were analyzed. Selected samples were subjected to microstructural analysis. The obtained results show an increase in hardness from 46 HB to 90–126 HB, and a further increase to 150–190 HB with a quasi-linear decrease of electrical conductivity, which proved the influence of solid-solution and strain hardening, respectively. The microstructural analysis proved that such deformation does not cause microcracks. Furthermore, in the case of CuMg up to 3 wt.% of Mg, the alloying additive completely dissolved after solutioning.

The enhanced aging hardening behavior in Si-containing Al-5Zn-1Mg-1Cu alloys

Abstract The ageing behaviour and phase transformation of a range of Si-microalloyed low Mg/Zn ratio Al-5.0Zn-1.0Mg-Cu alloys were investigated at a temperature of 150°C by using TEM and microhardness tests. Adding Si had a important influence on the proportion of precipitates and microhardness. As Si content increased, the precipitated phase underwent a gradual transition from the T+η precipitates to the fine GPB-II precipitates. Concurrently, the microhardness exhibited a notable enhancement from 120 HV to 150 HV when the alloys were subjected to 150°C aging. Existence of small and even GPB-II phases in the Si-adding alloy was identified as underlying cause of this result. This GPB-II phase exhibited a bilayer microstructure. In core region predominantly comprise Zn, Si and Mg, and the shell region primarily consist of Zn and Cu. This structure effectively inhibited phase growth, maintaining the phases at a smaller scale and enhancing the alloy’s hardening effect.

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.

Dealloying of Mg-based alloys for production of self-supporting metallic nanostructures

Dealloying is a proficient technique in the fabrication of nanostructured metals, particularly nanoporous materials, with promising potential for diverse applications. However, the development of robust and self-standing nanostructured metal foils through dealloying presents significant challenges. By generating an alloy layer on the surface of the metal foil, nanostructures can be generated on the metal foil surface through subsequent dealloying. This approach utilizes the inherent flexibility and ductility of the metal foil to ensure self-support. It also allows for the tailoring of the structure and composition of the dealloyed nanostructured metal by manipulation of the phase constitution in the surface alloy layer. In this study, we report a strategy for generating alloy layers on metal foil surfaces through the thermal evaporation of magnesium (Mg) followed by annealing. Upon dealloying the surface alloy layer, we successfully obtain self-supported nanostructured metal foils. Employing copper (Cu) as an example, we demonstrate that Mg can form a Mg–Cu alloy layer on the surface of a Cu foil, where the control over the alloy layer's phase composition and thickness is achieved by adjusting the annealing duration. Furthermore, we investigated the feasibility of this method on nickel (Ni) substrates, including Ni foils and Ni foams. Moreover, by further functionalizing the resulting nanostructured Ni foil, we transformed it into Ni(OH)2/Ni foil and explored its performance in the electrocatalytic oxygen evolution reaction (OER). The resulting catalyst achieved a current density of 10 mA cm−2 at a potential of only 349 mV in a 1 M KOH solution, exhibiting a Tafel slope of 84.52 mV dec−1. Following 10 h of stability testing, the catalyst exhibited negligible degradation in performance. This study provides a convenient and versatile pathway for preparing self-supported nanostructured metals.

The Effect of the Percentage of Mg on the Properties of Cu-Mg Alloys Manufactured by Horizontal Continuous Casting Process

The Effect of the Percentage of Mg on the Properties of Cu-Mg Alloys Manufactured by Horizontal Continuous Casting Process

Prospective cold metal working and analysis of deformation susceptibility of CuMg alloys with high magnesium content

Metal alloys designated for cold metal working exhibit much higher strength properties than pure materials due to solid-solution hardening. However, with the increase of mechanical properties its plasticity and workability decreases. Constant development and demand in this area has led to research on many copper alloys, such as copper alloys with high content of magnesium which were never tested before. The limitations regarding cold metal working of CuMg alloys is the main objective of this paper. Here we show that the tested materials exhibit much higher mechanical properties than currently used as electric conductors and carrying-conducting equipment materials such as pure copper, aluminum, M63 brass or CuNiSi alloy. The results were obtained using Hollomon relation, Considére criterion, Gubkin method and hardness measurements. It lead to assessing the prospective cold metal working of CuMg alloys with 2 wt% of magnesium up to 4 wt% of magnesium. The test range included upsetting with 10–50% of cold deformation. It provided the results on evolution of mechanical properties and deformability of tested alloys. Additional information was provided based on the alloys subjected to 50% of strain. The results have proven that as the amount of magnesium increased so did the assessed values, however, it was also linked with increasing friction coefficient. Measured hardness was 2 times higher and calculated Ultimate Tensile Strength (UTS) was even 2.5 times higher in reference to pure copper in the as-cast state. However, with magnesium content at 3.6 wt% or higher, the elevated amount of α + β phase causes brittleness making it impossible to subject these materials to cold metal working processes. We anticipate our assay to be a starting point for more sophisticated models and experimental research concerning cold metal working processes of CuMg alloys of high-strength, which may lead to developing novel and promising set of alloys.

Towards high strength and ductility of Al–Cu-Mg alloy via cyclic and monotonic pre-straining followed by ageing

This article presents an investigation of the ageing response of modern high-strength aluminium alloy 2519 (Al–5.64Cu-0.33Mn-0.23Mg-0.01Si (wt%)) after cyclic strengthening (CS). The impact of the pre-straining value on the mechanical properties, microstructure and phase composition was elucidated via hardness and tensile testing, analytical transmission and orientation imaging electron microscopy. The results show that cyclic hardening has a significant impact on the ageing behaviour of the alloy. Applying cyclic pre-straining in conjunction with monotonic enhances strength and ductility at once. This novel high-performance treatment results in superior strength-ductility combination. The improved mechanical properties are attributed to the observed changes in microstructure. The introduction of vacancies and dislocations, by repetitive and elastic straining before artificial ageing, leads to great homogeneous structure and an increase in the number density and volume fraction of the main strengthening phases (θ′ and Ω) and clusters/zones. Therefore, this work should suggest a strategy for developing a novel treatment of aluminium alloys with excellent mechanical properties.

Microstructure, mechanical properties and corrosion behaviour of Mg-Cu and Mg-Cu-Mn alloys

Mg-Cu and Mg-Cu-Mn alloys, namely CM10, CM20, CM30, CM11, CM22, and CM32, were produced using the permanent die casting method for this research. The study focused on the impact of varying levels of manganese on the microstructure and mechanical properties of the Mg-Cu alloys. Multiple tests were conducted, including optical microscopy, scanning electron microscopy, X-ray diffraction, tensile test (room temperature), Vickers hardness test, and immersion test. An immersion test with a 3.5 wt% NaCl solution was used to estimate the corrosion rate of the alloys. According to the results of this study, the addition of manganese to Mg-Cu alloys decreased their grain size. The principal phases, such as α-Mg, Mg2Cu, and α-Mn as minor phases, were confirmed by XRD analysis. The maximum ultimate tensile strength (179 MPa) and hardness (55 HV) were attained in Mg-Cu alloys with 2 wt% manganese. Additionally, the presence of manganese considerably improved the corrosion resistance of the Mg-Cu alloys.

Mixing Properties of Cu-Mg Liquid Alloy Using Exponential Model

The Redlich-Kister (R-K) polynomial has been generally used to model the mixing properties of binary and higher order alloys. The interaction energy parameters of the R-K polynomial are assumed to be either linear or exponentially temperature-dependent. When these parameters are assumed to be linear temperature-dependent, the computed thermodynamic functions sometimes show unusual trends. But when they are assumed to be exponential temperature-dependent, such trends do not appear in the theoretical calculations. Therefore, the mixing properties of Cu-Mg liquid alloy have been studied using the exponential temperature-dependent parameters of the above-mentioned model. These parameters for excess Gibb’s free energy of mixing have been optimised using the experimental values of enthalpy of mixing and excess entropy of mixing. The study of thermodynamic properties involves the measurement of excess Gibb’s free energy of mixing, enthalpy of mixing and activities of monomers at different temperatures. Likewise, the assessment of surface property includes surface tension and surface concentration. Similarly, the structural properties have been studied by computing concentration fluctuation in long wave-length limit and short-range order parameter at different temperatures. The investigation revealed that the exponential model can explain mixing behavior of Cu-Mg liquid alloy and the system is found to have strong compound forming tendency at its melting temperature. This mixing tendency has been observed to decrease with the increase in temperature above its melting temperature.

Material flow behavior and mechanical characterization of dissimilar friction stir welded Cu-Mg alloy joints

Magnesium alloys are considered to be the lightest material, whereas pure copper is known for better electrical and thermal conductivity finds their applicability especially in automotive and electronic industries. Joining of pure copper and Mg alloy has been studied by many researchers. However, very limited work are available for joining of Cu alloy with Mg Alloy. In the present study, friction stir welding was performed to join Cu-8Zn alloy and Mg AZ31 alloy plates of 3 mm thickness. The process parameters were selected as 1200 rpm rotational speed, 20 mm/min traverse speed, 3° tilt angle, and 0.5 mm tool offset towards copper side. The weld samples were studied for microstructural and mechanical properties. The obtained results by SEM and XRD revealed that there is a complex intercalated microstructure and Mg2Cu intermetallic compounds (IMCs) are present in the stir zone (SZ). Variation in hardness has been observed in the microstructure and maximum hardness of 162.54 HV was found in the SZ due to the presence of Mg2Cu and dynamic recrystallization of grains. The tensile strength of 72 MPa has been attained.

Pure Alloy Additive or Preliminary Alloy: A Comparative Study on Obtaining High-Strength Copper Magnesium Alloys Designed for Electrical Power Systems

Due to the increasing demand for electrical energy in modern society, there is a huge requirement for conducting materials and, due to the development of electromobility, this demand is forecasted to grow each year. This is one of the reasons why copper and copper alloys manufacturing and processing industries tend to evolve and improve. One of the improvement paths is the design of new conducting materials for electrical power systems, electrical energy transmission, and energy storage systems. This paper presents a comparative study on obtaining high-strength copper magnesium alloys in terms of the alloy additive used during the metallurgical synthesis process, because this is a crucial, initial element in obtaining the final conducting product, such as wires. The obtained ingots were tested in terms of their chemical composition, and mechanical and physical properties. The provided results prove that there is a significant increase in the materials’ hardness (and thus the ultimate tensile strength), and a slight decrease in density, impact resistance, and electrical conductivity, as the Mg content increases. Scanning electron microscopy (SEM) and phase analysis were additionally conducted in order to determine the distribution and origin of Mg precipitations. Collectively, the results show that the CuMg alloys may successfully replace other alloys, such as CuNiSi or CuZn, as carrying and conducting materials because their properties are superior to those of the aforementioned materials.

Enhanced initial biodegradation resistance of the biomedical Mg-Cu alloy by surface nanomodification

Mg-Cu alloys are promising antibacterial implant materials. However, their clinical applications have been impeded by their high initial biodegradation rate, which can be alleviated using nanotechnology by for example surface nanomodification to obtain a gradient nanostructured surface layer. The present work (i) produced a gradient nanostructured surface layer with a ∼500 µm thickness on a Mg-0.2 Cu alloy by a surface mechanical grinding treatment (SMGT), and (ii) studied the biodegradation behavior in Hank's solution. The initial biodegradation rate of the SMGTed samples was significantly lower than that of the unSMGTed original counterparts, which was attributed to the surface nanocrystallization, and the fragmentation and re-dissolution of Mg2Cu particles in the surface of the SMGTed Mg-0.2 Cu alloy. Furthermore, the SMGTed Mg-0.2 Cu alloy had good antibacterial efficacy. This work creatively used SMGT technology to produce a high-performance Mg alloy implant material.

Wire-arc additive manufacturing of Al-Zn5.5-Mg-Cu (ML7075): Shifting paradigms of additive manufacture-ability

Al-Zn-Mg-Cu alloys belong to the highest-performing aluminum alloys and are in focus for processing by additive manufacturing with limited success so far. The reason is that these alloys severely tend to hot-cracking. We present results of microstructure and mechanical properties after wire-arc additive manufacturing of an AlZn5.5MgCu alloy. Specimens are crack-free and reach mechanical property values similar to wrought AlZn5.5MgCu. We suggest that the intrinsic heat-treatment affects the processability of this alloy.

Effect of Al addition and heat treatment on the microstructures and corrosion resistance of Mg-Cu alloys

The effects of Al content and annealing condition on the microstructures and corrosion performances of Mg-3 wt.%Cu-xAl (x = 0, 4 wt.%, 8 wt.%) alloys were investigated. The Mg-3 wt.%Cu alloy contains Mg2Cu phase, but Al-bearing alloys contain MgAlCu and Mg17Al12 phases. The Mg2Cu and MgAlCu phases exhibit much higher Volta potential compared to Mg17Al12 and α-Mg, and their volume fractions are related to Al content of alloys and annealing condition. The weight loss measurement and electrochemical tests are conducted to explore the corrosion performances of alloys. The close relationship between weight loss rate of alloys and volume fraction of Cu-bearing phases indicates that the corrosion performances of alloys can be controlled by adjusting Al content of alloys and annealing conditions.

Macroporous and Antibacterial Hydrogels Enabled by Incorporation of Mg-Cu Alloy Particles for Accelerating Skin Wound Healing

Macroporous and Antibacterial Hydrogels Enabled by Incorporation of Mg-Cu Alloy Particles for Accelerating Skin Wound Healing

Comparison of the semisolid squeeze casting and gravity casting process on the precipitation behavior and mechanical properties of the Al-Si-Cu-Mg alloy

The differences in microstructure, ageing behavior and mechanical properties of the Al-17.8Si-4.3Cu-0.4Mg alloy formed by semisolid squeeze casting and gravity casting processes were investigated. It was found that a nearly equiaxed microstructure of α-Al, finer and denser Si phases, and a higher dislocation density exist in the semisolid extruded sample. In the peak ageing state, θ” and Q' phases are mainly observed under the two forming processes, while the precipitate increases and the size decreases after semisolid extrusion. According to the thermodynamics, the binding energy and enthalpy values of Q′ phase are lower than those of the θ' and θ″ phases. Therefore, among the three metastable phases, the Q′ phase precipitated before the θ″ and θ' phases. The semisolid extruded alloy exhibits higher strength and ductility in the as-cast state and T6 state. This might be caused due to more uniform microstructure and finer precipitating phase. Double ageing hardness peaks were found in the age-hardening curves of Al-17.8Si-4.3Cu-0.4Mg alloys under both processes, which were related to the influence of the precipitation sequence of the alloy. • Microstructure and properties of Al-Si -Cu-Mg alloy by semisolid extrusion and gravity casting was studied. • Better comprehensive mechanical properties were obtained after semisolid squeeze casting process. • There were two hardness peaks corresponding to the ageing time of 6 and 12 h under two forming processes. • Compared to gravity casting, the size of the precipitates in the semisolid extruded samples was smaller.

High strength-ductility and rapid degradation rate of as-cast Mg-Cu-Al alloys for application in fracturing balls

• As-cast Mg-2.5Cu-xAl (x = 4.5, 6.0 wt.%) alloys were developed for application in fracturing balls. • The degradable Mg-2.5Cu-6.0Al alloy exhibits a combined high compressive strength (378 MPa), good compressive strain (27%) and rapid degradation rate (383 mm/y). • The addition of Al could improve the strength and ductility simultaneously in Mg-2.5Cu alloy. • A discontinuous network of β-Mg 17 Al 12 +Al 2 Cu and MgAlCu phases is formed in the immersion tests, acting as cathodes to accelerate micro-galvanic corrosion. Specially designed Mg-Cu-Al alloys were prepared for the application in fracturing balls. In comparison to Mg-2.5Cu alloy, Mg-2.5Cu-6.0Al alloy exhibits an improved compressive strength of 378 MPa and compressive strain of 27%, combined with a high degradation rate of 383 mm/y. Two kinds of second-phases are found in Mg-Cu-Al alloys, i.e. MgAlCu and β-Mg 17 Al 12 +Al 2 Cu phases. They form a discontinuous network and act as cathodes for micro-galvanic corrosion, leading to a high degradation rate. Moreover, the addition of Al could improve the strength and ductility simultaneously in Mg-Cu alloys. The enhancement of strength primarily arises from the solid-solution strengthening and second-phase hardening. A high density of basal, non-basal dislocations and stacking faults were activated upon mechanical deformation. This accounts for the good ductility in Mg-Cu-Al alloys.

Treatment of copper-cobalt alloy with molten magnesium for metal extraction

Cu-Co alloy is an intermediate product from the pyrometallurgical processing of cobalt oxide ores, which mainly contains metallic components of Cu, Co, Fe and Si. This research aims to extract Cu from Cu-Co alloy by selective dissolution using molten Mg. The alloy particles were mixed with Mg and held at temperatures in the range 700–900 °C for 0.5–2 h. The residual Fe-Co-Si alloy settled to the bottom of the melt due to the density difference between the alloy and molten Mg. Under optimal conditions, as much as 99 wt% Cu can be selectively extracted from the alloy by dissolution into the molten Mg. Vacuum distillation at 900 °C was applied to the obtained Mg-Cu alloy, resulting in the formation of Cu power with 80 wt% purity. The recovered Mg metal after distillation could potentially be recycled for re-use. Therefore, this process achieved efficient extraction of Cu without the consumption of Mg and generation of waste, representing an effective and environmentally-sound approach for the processing of Cu-Co alloy.

The Influence of the Continuous Casting Conditions on the Properties of High-Strength Two-Phase CuMg Alloys.

Constant tendency toward the improvement of the material properties nowadays creates opportunities for the scientists all over the world to design and manufacture new alloys almost every day. Considering the fact that companies all over the world desire alloys with the highest values of mechanical properties often coexisting with a reasonable electrical conductivity made it necessary to develop new materials based on Cu, such as CuMg alloys. However, before such new material may be mass produced it must undergo a series of tests in order to determine the production technology, its parameters and influence on the chemical composition, microstructural properties, and both mechanical and physical properties of CuMg alloys. The research tests have shown that with the increase of the casting feed the Brinell’s hardness of each material slightly increases (by 5 HB2.5/62.5). There is little to none impact of the casting feed on the electrical conductivity, values of which are between 20.6 and 21.4 MS/m (around 40% IACS-International Annealed Copper Standard) depending on the Mg content. The conducted scanning electron microstopy (SEM) analysis has shown that the magnesium precipitations are evenly distributed among the volume of the alloy, however, a significant difference in the density and shape of the Cu + Cu2Mg aggregates was noticed regarding various casting feed. Static compression test proved that these alloys may be subjected to strain hardening as the hardness of the material after compression increases by approximately 40 HB2.5/62.5.

An Antibacterial Strategy of Mg-Cu Bone Grafting in Infection-Mediated Periodontics.

Periodontal diseases are mainly the results of infections and inflammation of the gum and bone that surround and support the teeth. In this study, the alveolar bone destruction in periodontitis is hypothesized to be treated with novel Mg-Cu alloy grafts due to their antimicrobial and osteopromotive properties. In order to study this new strategy using Mg-Cu alloy grafts as a periodontal bone substitute, the in vitro degradation and antibacterial performance were examined. The pH variation and Mg2+ and Cu2+ release of Mg-Cu alloy extracts were measured. Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), two common bacteria associated with periodontal disease, were cultured in Mg-Cu alloy extracts, and bacterial survival rate was evaluated. The changes of bacterial biofilm and its structure were revealed by scanning electron microscopy (SEM) and transmission electronic microscopy (TEM), respectively. The results showed that the Mg-Cu alloy could significantly decrease the survival rates of both P. gingivalis and A. actinomycetemcomitans. Furthermore, the bacterial biofilms were completely destroyed in Mg-Cu alloy extracts, and the bacterial cell membranes were damaged, finally leading to bacterial apoptosis. These results indicate that the Mg-Cu alloy can effectively eliminate periodontal pathogens, and the use of Mg-Cu in periodontal bone grafts has a great potential to prevent infections after periodontal surgery.