Effect Of Mg Content Research Articles

Effect of Mg content on structure and hydrogen storage properties of YNi2.1 alloy

The Y1-xMgxNi2.1 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) alloys were prepared by sintering method in this work. The effect of Mg on structural transformation, hydrogen storage properties, and structural stability were investigated. It is found that with the increase of Mg substitution the abundance of (Y, Mg)Ni2 phase increases and the total amount of (Y, Mg)Ni3 and (Y, Mg)2Ni7 phases first increases and then decreases. Mg preferentially enters into the (Y, Mg)Ni2 phase. When the Mg content in (Y, Mg)Ni2 phase is higher than 0.2, the (Y, Mg)Ni2 phase forms and does not undergo hydrogen induced amorphization and disproportionation. The hydrogen storage capacity decreases owing to the transformation from (Y, Mg)Ni2 phase to the more stable (Y, Mg)Ni3 phase. When the Mg content in (Y, Mg)Ni2 phase increases to 0.5, the atomic radius ratio of A-side to B-side reduces to less than 1.37, there is no capacity attenuation after 50 cycles.

Effect of Mg content on structure and corrosion behavior of novel hot-dip Al-Zn-Si-rE-Mg coatings

• Novel Al-Zn-Si-RE-Mg coatings with different Mg contents were produced by continuous hot-dip galvanizing. • Mg led to the formation of double-layer or triple-layer dendrites, as well as MgZn 2 and Mg 2 Si phases. • Mg promoted the generation of Zn-Al LDH, and retarded the corrosion of Al-rich dendrites. • The addition of 1 wt.% Mg had the best effect on the improvement of coating performance. In this work, the effect of Mg content on structure and corrosion behavior of novel hot-dip 55Al-Zn-1.5Si-0.08RE-xMg (wt.%) coatings were investigated. It was found that the addition of Mg element led to the formation of double-layer or even triple-layer dendrites, as well as induced the generation and distribution of MgZn 2 and Mg 2 Si phases. In addition, Mg also promoted the conversion of corrosion product film from porous AlO(OH) to dense Zn 6 Al 2 (OH) 16 CO 3 ·4H 2 O (Zn-Al LDH), and retarded the corrosion of Al-rich dendrites. When Mg content was 1.0 wt.%, the coating had the smallest dendrite structure, the most protective corrosion product film and the best corrosion resistance with corrosion current density of 2.7 μA/cm 2 and charge transfer resistance of 31550 Ω·cm 2 .

Effects of Mg contents on microstructures and second phases of as-cast Al–Zn–Mg–Cu alloys

The effects of Mg content on the microstructures and second phases of the as-cast Al–Zn–Mg–Cu alloys were investigated. The results show that the nonequilibrium eutectic structure consists of α(Al), Al7Cu2Fe, η(MgZn2) and T(AlCuMgZn) intermetallic compounds. The alloys with the highest Mg content generate nonequilibrium eutectic structures. The maximum value of nonequilibrium eutectic structures is 10.13 ± 0.62%. As the Mg content increases, the number of tertiary dendrites in the α(Al) matrix increases significantly, and more Mg can be dissolved into the Al- matrix. In addition, as the Mg content increases, the crystallization temperature range decreases from 169.8 K to 157.3 K. When the Mg content is higher than 2.6 wt%, the microstructure evolution of the Al–Zn–Mg–Cu aluminum alloy is as follows: Liq. → Liq. + α(Al) → Liq. + α(Al) + Al7Cu2Fe → α(Al) + Al7Cu2Fe + η(MgZn2) + T(AlCuMgZn). These results play a certain role in promoting the basic research of Al–Zn–Mg–Cu aluminum alloys with high Mg content.

Influence of Mg on tensile deformation behavior of high Mg-content Al-Mg alloys

Al-Mg based alloys are known to experience dynamic strain aging (DSA) at room temperature, which is often associated with the diffusion of mobile Mg atoms to dislocation segments temporarily arrested at obstacles (e.g., forest dislocations) upon deformation in the DSA regime. With the emergence of new promising high Mg-content (> 6 wt.%) Al-Mg alloys, the combined effects of Mg content and DSA on their tensile flow behavior need to be better understood. In the present work, the tensile deformation behavior of Al and Al-(5.3, 6.4, 7.6 and 8.7) wt.% Mg samples tested at room temperature and at strain rates ranging from 0.0001 to 0.1 s−1 was investigated, based on the Kocks-Mecking-Estrin model combined with a DSA model, the Haasen plot as well as transmission electron microscopy. Particular focuses are placed on the influence of Mg solutes on DSA and associated strain hardening effects, on dislocation accumulation and annihilation as well as on apparent activation volume. We show that the synergistic effect of the Mg-dislocation interactions and DSA effectively reduces the rate of dynamic recovery via suppressing dislocation cross-slip, leading to an enhanced strain hardening capacity for the Al-Mg alloys with a higher Mg content. The influences of DSA on the yield strength, flow stress and apparent activation volume of thermally-assisted deformation of the Al-Mg alloys are also discussed to elucidate fundamental insights into the development of new high Mg-content Al-Mg alloys with superior mechanical performance.

Evolution of Inclusions and Microstructure in Ca‐La‐Treated C‐Mn Steel with Different Mg Contents

Herein, the effect of Mg content on inclusions and microstructure of Ca‐La‐treated steel is investigated. Inclusions mainly consist of oxide cores, La‐containing parts, and sulfides in the final quenched samples. Oxide cores are Ca‐Al‐O in Mg‐free sample, whereas those in Mg‐bearing samples change from Mg‐Ca‐Al‐O and Mg‐Al‐O to MgO with the increasing Mg content. Increasing Mg content from 0 to 0.003%, the number density of inclusions increases while mean size decreases due to the formation of fine Mg‐containing inclusions. When Mg content is 0.0053%, the formation of sulfides (MgS and CaS) with high contact angle promotes the aggregation of inclusions, which results in the decrease of number density of inclusions and the increase of inclusions size. Effective inclusions are predominantly composed of oxide cores and MnS shells. A large amount of acicular ferrite (AF) is obtained in low and medium Mg content samples due to the formation of a mass of effective inclusions. High Mg content leads to the formation of MgS and CaS and suppresses the precipitation of MnS, which decreases the effectiveness of inclusions to induce the formation of AF.

Additive manufacturing of biodegradable Zn-xMg alloys: Effect of Mg content on manufacturability, microstructure and mechanical properties

Additive Manufacturing (AM) exhibits tremendous advantages in producing customized medical implants and has achieved successful clinical applications for non-degradable metals such as titanium, stainless steel and cobalt alloys, particularly in the form of porous scaffolds for bone implants. Biodegradable materials allow the metal to degrade while natural tissue grows thereby reducing implant lifetime within the body to a minimum. The design freedom of AM and especially Laser Powder Bed Fusion (LPBF) overcomes technical difficulties of conventional technologies to manufacture complex structures. Within this work test geometries and porous scaffolds were manufactured via LPBF with pre-alloyed Zinc-Magnesium (Zn-xMg) powder, where x = 0, 1, 2 and 5 wt% to investigate the effect of Mg on manufacturability, microstructure and mechanical properties. Relative material densities of cubic specimens above 99.5% were achieved with all pre-alloyed powders. The addition of Mg reduces the processing window compared to pure Zn. A decreased grain size and an increase in intermetallic precipitates is observed with the addition of Mg. Zn-1Mg samples exhibited 3.2x the maximum ultimate tensile strength (UTS) of pure Zn (i.e., 119 MPa). However, the tensile elongation is only a fifth compared to pure Zn. With increasing Mg content, the amount of Zn+Mg2Zn11 rises and MgZn2 forms. These brittle phases characteristically increase hardness but reduce ductility. Under the chosen processing conditions, all Zn-xMg scaffolds demonstrated good processability. The geometric porosity was designed to be 80.5% with the achieved value of 70.8 % for compression testing. Zn-1Mg scaffold showed the highest compressive strength and Young’s modulus (19.1 MPa and 0.65 GPa respectively). This paper summarizes the technical challenges of manufacturing Zn-xMg alloys via LPBF for tissue engineering applications.

Effects of Mg content on microstructure and mechanical properties of low Zn-containing Al−xMg−3Zn−1Cu cast alloys

Effects of Mg content on the microstructure and mechanical properties of low Zn-containing Al−xMg− 3Zn−1Cu cast alloys (x=3−5, wt.%) were investigated. As Mg content increased in the as-cast alloys, the grains were refined due to enhanced growth restriction, and the formation of η-Mg(AlZnCu)2 and S-Al2CuMg phases was inhibited while the formation of T-Mg32(AlZnCu)49 phase was promoted when Mg content exceeded 4 wt.%. The increase of Mg content encumbered the solution kinetics by increasing the size of eutectic phase but accelerated and enhanced the age-hardening through expediting precipitation kinetics and elevating the number density of the precipitates. As Mg content increased, the yield strength and tensile strength of the as-cast, solution-treated and peak-aged alloys were severally improved, while the elongation of the alloys decreased. The tensile strength and elongation of the peak-aged Al−5Mg−3Zn−1Cu alloy exceed 500 MPa and 5%, respectively. Precipitation strengthening implemented by T′ precipitates is the predominant strengthening mechanism in the peak-aged alloys and is enhanced by increasing Mg content.

Partially biodegradable Ti Mg composites prepared by microwave sintering for biomedical application

Partially biodegradable TiMg composites were prepared by microwave sintering using the elemental Ti and Mg powders. The effect of Mg contents on the microstructure, mechanical properties, corrosion resistance, Mg degradation behavior of the TiMg composites was investigated. The number of block Mg distributed over the Ti matrix gradually increases with increasing the Mg contents, in which the Mg and Ti form the metal-metal composite, and the interface of Mg and Ti is well bonded. The compressive strength of the TiMg composites gradually decreases from 625 MPa to 357 MPa with increasing the Mg contents, while the elastic modulus varies little, ranged from 4.8 GPa to 5.7 GPa. The corrosion resistance of the TiMg composites in SBF solution gradually decreases with increasing the Mg contents, resulting in the increase of hydrogen evolution amount. According to the electrochemical impedance spectroscopy, the corrosion and degradation of the TiMg composites in SBF solution can be divided into three stages: the corrosion and degradation of Mg, the formation of Mg(OH)2 layer and the dissolve of Mg(OH)2 layer coupled with the formation of hydroxyapatite layer.

Additive Manufacturing of Biodegradable Zn-Xmg Alloys: Effect of Mg Content on Manufacturability, Microstructure and Mechanical Properties

Additive Manufacturing of Biodegradable Zn-Xmg Alloys: Effect of Mg Content on Manufacturability, Microstructure and Mechanical Properties

Effect of Mg Content on Structure and Hydrogen Storage Properties of Yni2.1 Alloy

Effect of Mg Content on Structure and Hydrogen Storage Properties of Yni2.1 Alloy

Microstructure and mechanical behavior of Al-xMg/5Al2O3 nanostructured composites

The effect of Mg content and milling time were investigated on the microstructure and microhardness values of Al-xMg/5Al2O3 (x = 0, 4, 8 and 12 wt %) nanostructured composite prepared via high energy milling technique. XRD results showed an acceleration of alloying process and formation of Al (Mg) ss by enhancing percentage of Mg element. Also, by increase in Mg percentage the grain size reduction was more considerable during milling treatment. Additionally, increment of the Mg content up to 12 wt%, causes the increase in micro-strain of the samples (from 0.31 to 0.82%). Increase in Mg concentration accelerates the mechanical milling process. According to SEM results a coaxial and circular morphology with a uniform distribution of powder particles has been formed. Up to 12 wt% (for each milling time), significant increase in microhardness (215 HV) was carried out due to solid solution hardening and crystallite refinement. From 10 to 15 h, a slight increase in microhardness up to 218 HV can be observed.

Effect of Mg Content on Synthesis of TiC Powder from Leucoxene by Self-Propagating High-Temperature Synthesis Method

Titanium carbide (TiC) composite powder was synthesized via the self-propagating high-temperature synthesis (SHS) method using leucoxene as a source of titanium oxide (TiO2) and magnesium (Mg) as an initiator. The effect of Mg content on synthesized TiC composite powder was characterized in terms of chemical composition and morphology by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Results showed that adding 1.5 moles Mg into the reactant system leached with 0.1 M hydrochloric acid solution was the optimal condition, and TiC was apparent in the XRD analysis at a particle size of less than 150 μm.

Effect of grain size and volume fraction of eutectic structure on mechanical properties and corrosion behavior of as-cast Zn–Mg binary alloys

In this work, the effects of Mg content on the microstructure evolution, mechanical properties, and corrosion behavior of as-cast Zn-xMg (x = 0.1, 0.3, 0.5, 1.0, 1.5, and 3.0, wt.%) binary alloys were investigated. The microstructure of as-cast alloys is composed of α-Zn matrix and a ternary eutectic phase (α-Zn + Mg2Zn11+MgZn2). With the increase of Mg content, the average grain size of the alloys decreases from 104 μm to 11 μm while the volume fraction of eutectic structure increases from 3% to 84%, resulting in the improvement of tensile strength. In vitro immersion tests demonstrate that the corrosion rate decreases to a minimum value of 0.086 mm y−1 as Mg content increases from 0.1 to 0.3, followed by an increasing trend with the further increase of Mg content. The variation of corrosion rate with Mg content originates from the competition between the positive effect of grain refinement and the negative effective of eutectic volume fraction increment. Zn-0.3 Mg alloy has the optimal corrosion resistance because of the dominant role of grain refinement induced corrosion resistance enhancement. In addition, the corrosion mechanism varies from localized pitting to a more uniform corrosion as Mg content rises.

Effect of Mg content on the dislocation characteristics and discontinuous dynamic recrystallization during the hot deformation of Al-Mg alloy

The effect of Mg content on the dynamic recrystallization behavior during the hot deformation of Al-Mg alloys were investigated. Three different Mg contents of Al-6Mg, Al-8Mg, and Al-9Mg were hot-torsioned under the deformation temperature of 723 K and a strain rate of 0.1 s−1. Using and electron backscatter diffraction, the dislocation characteristics during the hot deformation of each alloy were evaluated. The results of X-ray line profile analysis showed that the strain anisotropy parameter and dislocation arrangement parameter decreased when the strain increased, and when the fraction of edge dislocation and screening of dislocation field (interaction between dislocations) increased. However, the variation in Mg content affected the strain dependence of the dislocation parameters, which means that the Mg content in the Al-Mg alloy affected dislocation characteristics and dynamic recrystallization. In addition, the fraction of low-angle boundaries was accelerated when the strain increased at lower Mg content, while the formation of serrated grain boundaries was remarkably observed. Consequently, considering the absence of twinning, at all strains, higher Mg content increased the dynamic recrystallization rate and induced the flow softening at relatively low strains.

Effect of magnesium content and growth temperature on structural and optical properties of USCVD-grown MgZnO films

Magnesium zinc oxide (MgxZn1-xO) films (x < 0.4) have been grown by ultrasonic spray chemical vapor deposition on soda-lime glass substrates for different growth temperature and different Mg mole fractions (x). Effects of Mg content in the liquid solution and the effect of growth temperature on optical and structural properties of MgZnO films have been investigated with X-ray diffraction, atomic force microscope, and UV–visible spectrophotometry measurements. The growth temperature has a significant effect on determining the Mg mole fractions of MgZnO films. There is a linear correlation between the measured Mg mole fraction in the resulted grown structures and Mg content in the solution. The peak of (0002) diffraction for the grown samples has been shifted to the higher diffraction angles with increase in Mg content in the liquid solution and has also become stronger. The growth temperature and Mg content in a liquid solution are crucial parameters in the controlling Mg mole fraction of samples.

Effects of Mg Content on Electric and Mechanical Properties of Al-Zn-Cu Based Alloys.

Microstructure and properties of Al-2 wt.%Zn-1 wt.%Cu-xMg (x = 0.1, 0.3, 0.5, 0.7 wt.%) alloy extrusion materials were investigated. The lattice constants for the (311) plane increased to 4.046858, 4.048483, 4.050114 and 4.051149 Å with the addition of 0.1, 0.3, 0.5, and 0.7 wt.% of elemental Mg. The average grain size of the as-extruded Al alloys was found to be 328.7, 297.7, 187.0 and 159.3 μm for the alloys with 0.1, 0.3, 0.5, and 0.7 wt.% Mg content, respectively. The changes in the electrical conductivity by the addition of elemental Mg in Al-2 wt.%Zn-1 wt.%Cu alloy was determined, and it was found that for the addition of 0.1, 0.3, 0.5, and 0.7 wt.% Mg, the conductivity decreased to 51.62, 49.74, 48.26 and 46.80 %IACS. The ultimate tensile strength of Al-2 wt.%Zn-1 wt.%Cu-0.7 wt.%Mg alloy extrusion was increased to 203.55 MPa. Thus, this study demonstrated the correlation between the electrical conductivity and strength for the Al-2 wt.%Zn-1 wt.%Cu-xMg alloys.

Achieving high damping and excellent ductility of Al[sbnd]Mg alloy sheet by the coupling effect of Mg content and fine grain structure

Fine-grained Al-xMg (x = 4.5, 6.5 and 9.2, in wt%) alloy sheets with high damping capacity and excellent ductility are prepared by high strain rate rolling (HSRR). Both the damping capacity and the mechanical properties of the alloys are improved compared with the as-homogenized states and increase with the higher Mg content. The three AlMg alloys exhibit similar strain-amplitude-independent damping capacities and the Al-9.2 Mg alloy is a little bit higher. While the strain-amplitude-dependent damping capacity increases with increasing the Mg content in a large strain amplitude range. The as-HSRRed Al-4.5 Mg, Al-6.5 Mg and Al-9.2 Mg alloys exhibit the damping values (Q−1) of 0.0140 ± 0.0005, 0.0167 ± 0.0006 and 0.0178 ± 0.0008 at the strain amplitude of 1 × 10−3. Furthermore, a combination of high ductility (42.8 ± 1.5%), moderate strength (435 ± 2 MPa) are also achieved in the Al-9.2 Mg alloy. The improved damping capacity of the as-HSRRed Al-9.2 Mg alloy are mainly attribute to the low stacking fault energy and the movement of the extended dislocation, the latter of which interaction with Suzuki atmosphere and thus increases energy consumption which plays a dominant role in the damping mechanism of the as-HSRRed alloys. The results of the present study provide new ideas for the development of high damping alloys with high mechanical property.

Effect of Mg content on electronic structure, optical and structural properties of amorphous ZnO nanoparticles: A DFTB study

In this work, we perform a theoretical analysis of structural, electronic, and optical properties of pure and Mg-doped amorphous ZnO nanoparticles (a-ZnO NPs) using DFTB method. Our results show that Zn atoms are more preferential for Mg atoms than for O atoms because the number of MgZn bonds is greater than that of MgO. The rise in the content of Mg in a-ZnO NPs leads to an increase of Mg–Zn and MgO interactions. Mg atoms prefer to locate near the center of a-ZnO NP, but Zn and O atoms nearly preserve their positions which is compatible with radial distribution function peaks. The orbital energies display a decrease in the energy gap from 3.592 to 3.546 eV while increasing Mg content. The LUMO level is also significantly shifted to higher energies. The results also reveal that the performance of pure a-ZnO NP can be enhanced with a subsequent increase in Mg content.

The effect of Mg content and milling time on the solid solubility and microstructure of Ti–Mg alloys processed by mechanical milling

This research presents a high energy ball milling method for producing supersaturated solutions of the Ti100-xMgx (x = 10, 15, 20) composite powders containing a process control agent (PCA) under an argon atmosphere at an ambient temperature. The microstructure of the Ti–Mg solid solution during milling was analyzed by scanning electron microscope, and an X-Ray diffraction. A particle size analyzer was employed to investigate the average particle size at different milling times (12 h, 20 h, 32 h). After milling for 32 h of Ti100-xMgx (x = 10, 15, 20) composite powders, the solid solubility of the Mg in Ti reached about 0.5 wt.%, 1.14 wt.%, and 1.92 wt.%, respectively. It was found that the crystallite size of the milled powder decreased by increasing the milling time and reached the value of 4–11 nm after 32 h of milling. Moreover, the addition of the process control agent after 12 h and 20 h significantly reduced the agglomeration by cold welding. As a result, the average particle size of the dispersed composite powder Ti100-xMgx (x = 10, 15, 20) was refined to about 1 μm which indicated that the Ti controlled the final size as being a major alloying element. The maximum value of the density of green compacts was found to be 2.69 g/cm3 for Ti–10Mg.

Effect of Mg content on microstructure and properties of Zn-Al-Cu Alloy

Zn-Cu-Al-xMg (x=0,0.25,0.5) zinc alloy was prepared by metal mould casting. The effects of Mg addition on the structure, electrical conductivity and mechanical properties of Zn-Al-Cu alloy were studied. The results show that without Mg addition, the alloy consists of Zn solid solution(ƞ phase) containing of Cu and Al and layered α+η eutectic structure. With the addition of Mg, the η phase grains were refined, the layered eutectic structure disappeared, and the intermetallic compound Mg2Zn11 appeared, and its content increased with the increase of Mg content. The hardness of the alloy increases with the increase of Mg content. When the content of Mg is 0.5wt.%, the hardness reaches the maximum value of 151HV. Tensile strength and electrical conductivity first increase and then decrease. When the addition of Mg is 0.25wt.%, the maximum tensile strength and electrical conductivity are 270 MPa and 26.4% IACS, respectively. The wear mechanism of zinc alloy is a mixture of adhesive wear and abrasive wear, and the adhesive wear is dominant.