Influence Of Mg Content Research Articles

Influence of Mg Content on Microstructure Coarsening, Molten Pool Size, and Hardness of Laser Remelted Al(-x)-Mg-Sc Alloys.

Investigations leading to high-quality surfaces and optimized properties in laser remelted Al-Mg-Sc alloys remain scarce. Laser surface remelting (LSR) has been used for the final treatment of these alloys processed through additive manufacturing. However, the direct microstructure responses of the treated cast surfaces have not yet been investigated. In the present research, Al-3, 5, and 10 wt %-Mg-0.1 wt %-Sc alloys plates were processed using LSR to study the effects of local melting and rapid solidification. The morphology of the α-Al phase, microstructure coarsening, and hardness were mapped from the bottom to the top of the molten pools, varying with local Mg content and laser heat input (2.5 J/mm, 5 J/mm, and 10 J/mm). This study aimed to create a comprehensive map of the microstructures, hardness, and molten pool sizes under various conditions. The findings may help to optimize these alloys through understanding laser processing parameters. Methods used included CALPHAD computations, optical microscopy, SEM, EDS, image analysis, hardness tests, and heat flow models. The results obtained showed α-Al cell growth with bands in all alloys with hardness changes correlating with cell spacing and heat input. Higher Mg content resulted in more refined cells and a higher fraction of bands. Increased Mg content decreased the thermal diffusivity and enthalpy of melting, enlarging the molten pool size. Hardness increased with decreasing heat input and higher Mg content in the tested alloys, especially in the Al-10 wt %-Mg-0.1 wt %-Sc alloy as the heat input was varied.

Effects of Mg contents on microstructures and corrosion behaviors of homogenization Al-Zn-Mg-Cu alloys

This study delved into the influence of Mg content on the microstructure and corrosion behavior of homogenized Al-Zn-Mg-Cu alloys. The findings unveiled that alloys featuring a moderate Mg content showcased an exceptionally low immersion corrosion rate of 0.0789 mm/a. A notable 22.3 % reduction in average grain size led to a significant 57.2 % drop in immersion corrosion rate. Furthermore, the augmentation of the Mg(Zn, Al, Cu)2 phase within the grains contributed to a decrease in the maximum immersion corrosion depth of the alloy. These novel findings offer fresh insights and hold potential for enhancing the corrosion resistance of homogenized Al-Zn-Mg-Cu alloys.

Influence of Mg Content on the Corrosion Behavior and Precipitation of Aged Al-Cu-Li-xMg Alloys

Aluminum (Al)–copper (Cu)–lithium (Li) alloys are susceptible to environmental degradation, which limits the in-service lifetime of the components. Because of their complex composition, there are seldom studies focusing on corrosion behavior influenced by one single element, which is essential to clarify the corrosion mechanism. Herein, the sole influence of Mg on the corrosion behavior of Al–Cu–Li–xMg alloys was analyzed. Results revealed that the addition of Mg can affect the nucleation and precipitation process of the T1 precipitate, resulting in a difference of potential between grain interior and grain boundary. The precipitation of the T1 precipitate was promoted in a 0.7Mg alloy while impeded in a 1.1Mg alloy, due to the competition of Cu atoms and nucleation sites between T1 and S′. Two types of corrosion behavior of Al–Cu–Li–xMg alloys appeared due to the potential difference and continuity of grain boundaries. Continuous precipitates in grain boundaries and less precipitates within the grain are likely to cause intergranular corrosion (IGC), while more precipitates within the grain will result in pitting.

Influence of Mg Content on the Metallurgical, Hardness, and Tensile Behaviour of Zn-Al-Si-Mg Alloy in the As-Cast Condition

In this current article, an effort was made to briefly study the impact of magnesium content on the mechanical and metallurgical performance of as-cast Zn-Al-Si-Mg alloy. Zinc, aluminium, and silicon of appropriate weight quantities were melted in an electric furnace, and magnesium of varying quantities (1-5wt%) was added to the melt to obtain rectangular cast specimens. Microstructural, hardness and mechanical property analysis was conducted for the developed alloy in the as-cast condition. It was noted that an addition of Mg to the Zn matrix refines the grains but more than 3wt-% of Mg to the matrix forms clusters which deteriorate the property of the alloy in the as-cast condition. The value of hardness and tensile strength were noted to enhance, and ductility was observed to decrease from the baseline alloy to the alloy with 3wt% of Mg. Further addition of Mg decreased the properties of the alloy.

Influence of Magnesium Content on the Physico-Chemical Properties of Hydroxyapatite Electrochemically Deposited on a Nanostructured Titanium Surface

The aim of this research was to obtain hydroxyapatite (HAp)-based coatings doped with different concentrations of Mg on a Ti nanostructured surface through electrochemical techniques and to evaluate the influence of Mg content on the properties of HAp. The undoped and doped HAp-based coatings were electrochemically deposited in galvanostatic pulsed mode on titania nanotubes with a diameter of ~72 nm, being designed to enhance the adhesion of the HAp coatings to the Ti substrate. The obtained materials were investigated by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), and Fourier-Transform Infra-Red spectroscopy (FTIR). The adhesion of the coatings to the substrate was also evaluated with the help of the “tape-test” and the micro-scratch test. The morphology (SEM) of all the coatings is made of very thin and narrow ribbon-like crystals, with some alterations with respect to the Mg amount in the coatings. Thus, a concentration of 1 mM of Mg in the electrolyte leads to wider and thicker ribbon-like crystals, while a concentration of 1.5 mM in the electrolyte generated a morphology that resembles the undoped HAp. Both phase composition (XRD) and chemical bonds (FTIR) analysis proved the formation of HAp in all coatings. Moreover, according to XRD, all coatings have a strong orientation toward the (002) plane. Irrespective of the Mg content, all coatings registered an average roughness between approx. 500 and 600 nm, while the coating thickness increased after addition of Mg, from a value of 9.6 μm, for the undoped HAp, to 11.3 μm and ~13.7 μm for H/Mg1 and H/Mg2, respectively. In terms of adhesion, it was shown that the coatings a H/Mg2 had a poorer adhesion when compared to H/Mg1 and the undoped HAp (H), which registered similar adhesion, indicating that a concentration of 1.5 mM of Mg in the electrolyte reduces the adhesion of the Hap-based coatings to the nanostructured surface. The obtained results indicated that Mg concentrations up to 1 mM in the electrolyte can enhance the properties of HAp-based coatings electrochemically deposited on a nanostructured surface, while even a slightly higher concentration of 1.5 mM can negatively impact the characteristics of HAp coatings.

Additive manufacturing of Zn-Mg alloy porous scaffolds with enhanced osseointegration: In vitro and in vivo studies

Biodegradable metals (BM) and additive manufacturing (AM) are regarded revolutionary biomaterials and biofabrication technologies for bone repairing metal implants, the combination of both, namely AM of BM, is thus expected to solve the dual technical difficulties including "conventional medical metals are biologically inert and exist in the human body permanently" and "conventional manufacturing processes are inadequate to fabricate personalized implants of complicated structure”. This work additively manufactured biodegradable Zn-Mg alloy porous scaffolds by laser powder bed fusion (L-PBF). By using the pre-alloyed Zn-xMg (x = 1, 2 and 5 wt.%) powder and the optimized processing conditions, high fusion quality with the relative density greater than 99.5% was confirmed for the L-PBF parts. The influence of Mg content on microstructure, mechanical properties, in vitro corrosion, cytocompatibility, in vivo degradation, biocompatibility and osteogenic effect was investigated. Fine α-Zn grains and precipitation phases including Mg2Zn11 and MgZn2 were observed in the Zn-xMg L-PBF parts. The hardness increased, and the strength increases firstly and then decreased with increasing the Mg content. The compressive strength and elastic modulus of Zn-1Mg porous scaffolds reached the highest as 40.9 ± 0.4 MPa and 1.17 ± 0.11 GPa, respectively, equivalent to those of cancellous bone. The corrosion rate and cell viability slightly rose with increasing the Mg content. Histological analysis after 6-week and 12-week implantation in rabbit femurs showed enhanced bone formation around the Zn-1Mg porous scaffolds compared with pure Zn counterparts. In summary, Zn-1Mg porous scaffolds produced by L-PBF presented promising results to fulfill customized requirements of biodegradable bone implants. Statement of significanceAdditive manufacturing of biodegradable metal porous scaffolds is expected to solve the dual challenges from customized structures and bioactive function required for bone implants. It was the first to present a systematic in vitro and in vivo investigation into the compositions, microstructure, mechanical properties, biodegradation, biocompatibility and osteogenic effect of additively manufactured Zn-Mg alloy porous scaffolds. Reliable formation quality and performance evaluation was achieved by using the pre-alloyed Zn-xMg (x = 1, 2 and 5 wt.%) powder and the optimized laser powder bed fusion process. Although the Zn-1Mg scaffolds exhibited promising mechanical strength, biocompatibility, and osteogenic effect, their degradation rate needs to be further accelerated compared with the term of bone reconstruction.

Study on the influence of Mg content on the risk of hydrogen production from waste alloy dust in wet dust collector

We use a proprietary automatic Al–Mg alloy–water reaction test apparatus to compare the hydrogen evolution profiles of Al-xMg (x = 10%,20%) with different particle sizes, characterize the waste Al-xMg alloy dust particles before and after reaction through SEM, EDS, and XRD, and present a three-stage four-step hydrogen evolution model of Al-xMg (x ≤ 35%) alloy dust particles. It is discovered that the reaction of the Al–Mg alloy in water is a hydrogen evolution–adsorption–slow diffusion process. The particular β-Al3Mg2 in Al-xMg (x ≤ 35%) will adsorb the resulting hydrogen to form MgH+ and adhere to the surface of the particles. As the Mg content in the alloy increases, the hydrogen evolution reduces. The entire process lasts around 5–6 h, with maximum hydrogen conversion rate of 54% (Al–10%Mg, d (50) = 12 μm, α = 0.544). Our hydrogen evolution model provides very useful theoretical references for avoiding hydrogen explosion in Al–Mg alloy manufacturing facilities.

Towards understanding the influence of Mg content on phase transformations in the La3-xMgxNi9 alloys by in-situ neutron powder diffraction study

The present work is focused on the studies of the phase-structural transformations in the La3-xMgxNi9 (x ​= ​1.0, 1.1 and 1.2) alloys as active materials of negative electrodes in the Nickel-Metal Hydride (Ni/MH) batteries. The phase equilibria and phase-structural transformations in the alloys were probed by in situ neutron powder diffraction (NPD) at the temperatures ranging from 300 ​K to 1273 ​K using the measurements of the equilibrated alloys at 8 setpoint temperatures of 300, 973, 1073, 1123, 1173, 1223, 1248 and 1273 ​K.Prepared by induction melting initial alloys were found to be multi-phase structured, containing up to 6 individual intermetallic compounds with different stoichiometric compositions. With the increase of the temperature and holding time, various transformations took place in the studied alloys. These included the formations and transformations of super-stacking intermetallics with variable ratios (La ​+ ​Mg)/Ni, 1:3, 2:7 and 5:19.With increasing temperatures, several systematic changes took place. (a) Abundances of (La,Mg)2Ni4 AB2 and (La,Mg)Ni3 AB3 type intermetallics gradually decreased before they melted/decomposed above 1073 ​K; (b) The (La,Mg)2Ni7 A2B7 type intermetallics began to decrease in abundances above 1123 ​K; (c) The transformation in the (La,Mg)5Ni19 intermetallics from 3R to 2H proceeded above 1223 ​K.The increase of Mg content had no obvious influence on (La,Mg)2Ni4 and (La,Mg)2Ni7 phases, and corresponding reactions R1 and R3 took place at the same temperatures as in the La–Ni system. However, with increasing Mg content the melting point of (La,Mg)5Ni19 phase increased while the melting point of the (La,Mg)Ni3 phase it decreased, leading to the variation of the reaction temperatures of the corresponding processes.The present study will assist in optimizing phase-structural composition of the alloys in the La–Mg–Ni system which contain Mg-modified layered structures by tailoring the high temperature annealing conditions.

Influence of Mg Content on Texture Development during Hot Plain-Strain Deformation of Aluminum Alloys

The study addresses the effect of magnesium and other alloying elements on rolling “β-fiber” texture formation during hot deformation of aluminum alloys. For the study, flat cast ingots from three aluminum alloys with variable magnesium content were deformed in a Gleeble testing unit with different parameters of thermomechanical treatment. Immediately after completion of deformation, the samples were quenched using an automatic cooling system and the microstructure and crystalline texture was analyzed by optical microscopy and X-ray analysis. The analysis demonstrated that an increase in alloying components, magnesium in particular, leads to an increase in brass-type texture and a decrease in S and copper-type texture. The reason was that the simulation of the deformation texture development revealed a great contribution of impurity atoms rather than the decrease in stacking fault energy.

Influence of Mg content in Al alloys on processing characteristics and dynamically recrystallized microstructure of friction surfacing deposits

Friction Surfacing (FS) coatings are deposited by severe plastic deformation at elevated temperatures (≈0.8*Tliquidus), requiring different process parameters for alloys of even small composition variations. For Al alloys it is known that with increasing Mg content the thermal softening rate decreases, i.e. the material retains higher flow strength under thermomechanical processing. Further, the stacking fault energy (SFE) decreases with increasing Mg content, which influences gliding characteristics of dislocations, and also deformation and recrystallization behavior. To elucidate the influence of such known properties on FS process parameters and resulting coatings, three Al alloys differing only in Mg content (0.27, 2 and 3.5 wt.%) were processed by FS in this study.Pronounced shear flow localization was observed for increasing Mg content, yielding thin and narrow coatings and requiring a reduction of process speeds. Further, the decrease in SFE with increasing Mg content resulted in lower recrystallized grain size and higher grain orientation differences, due to a lower tendency for dislocation annihilation by recovery.

Tuning of Mg content to enhance the thermoelectric properties in binary Mg2+δSi (δ = 0, 0.1, 0.15, 0.2)

We report the enhanced thermoelectric properties of binary Mg2Si by tuning the Mg content. Polycrystalline Mg2+δSi (where δ is the excess Mg content in the starting composition of the samples and δ = 0, 0.1, 0.15, 0.2) samples were processed by solid-state synthesis route using ball milling followed by rapid spark plasma sintering in order to minimize the Mg loss during processing. Microstructural and x-ray diffraction analysis revealed that, Mg content (δ) of 0.1–0.15 is required to get the binary Mg2Si phase without any elemental Mg/Si phase. Hall effect measurement and Fourier Transform Infrared Spectroscopy analysis show that, the excess Mg content helps to enhance the carrier concentration and charge carrier effective mass due to the occupancy of Mg at the interstitial site in Mg2Si structure. The influence of Mg content on thermoelectric properties, viz., electrical resistivity, Seebeck coefficient and thermal conductivity is investigated from 300 K to 780 K. A marked enhancement in thermoelectric power factor (∼1.6 mW m−2K−2) is obtained for Mg2.15Si sample at 780 K. The occupancy of excess Mg at interstitial sites reduces the lattice thermal conductivity by lowering lattice symmetry. A maximum figure of merit (ZT) ∼ 0.39 ± 0.03 at 780 K has been achieved in Mg2.15Si sample, the highest among that reported in n-type binary Mg2Si system. This suggests that excess Mg content in the starting composition of Mg2+δSi helps in stabilizing the phase as well as improves the thermoelectric properties of the Mg2Si.

Microstructure and Three-Point Bending Fatigue Behavior of Al-Cu-Mg-Ag Alloys with Various Mg Contents

This paper presents an investigation on the influence of Mg content on the microstructures, tensile properties and three-point bending fatigue behavior of Al-Cu-Mg-Ag alloys. The results indicate that the alloy containing 0.70 wt.% Mg possesses lower tensile properties and higher fatigue performance compared to the one with 1.15 wt.% Mg. Increasing Mg content in Al-Cu-Mg-Ag alloys can enhance the nucleation and precipitation of Ω phase, as well as increase the volume fraction and number density of constituent particles. The investigation of the fatigue crack initiation and growth behavior of Al-Cu-Mg-Ag alloy using interrupted fatigue tests suggests that micro-cracks mainly nucleate on Al2Cu constituent particles and the fatigue life is mainly associated with the density of constituent particles.

Structural and morphological evolution of Fe–rich phases in Al–xMg–6Si–4Fe alloys

In this paper, the influence of Mg content on the evolution of Fe–rich phases in Al– xMg–6Si–4Fe alloys has been investigated. It was found that the Fe–rich phase in Mg–free Al–6Si–4Fe alloy is α–AlFeSi with the chemical formula of Al15Fe3Si2, performing as polyhedral morphology. When the addition of Mg is 2 ​wt% and 4 ​wt%, part of α–AlFeSi particles evolve to flake–like Al13Fe4 phase. With further increase of Mg content to 6 ​wt% and 10 ​wt%, the morphological evolution of Al13Fe4 from flake–like to petal–like with ten branches was detected. The evolution mechanisms were supposed relating to the combination tendency between Mg and Si atoms and the enhanced undercooling level caused by Mg addition.

Influence of Mg on the mechanical properties and degradation performance of as-extruded Zn[sbnd]Mg[sbnd]Ca alloys: In vitro and in vivo behavior

The influence of Mg content on the mechanical properties, degradation behavior, in vitro cell adhesion, and in vivo behavior of as-extruded Zn-xMg-0.1Ca (x = 0.5 wt%, 1.0 wt%, 1.5 wt%) alloys was investigated. A high Mg content could increase the volume fraction of the hard Mg2Zn11 phase distributed at grain boundaries. This condition could significantly improve yield strength and ultimate tensile strength. Mg addition could adjust the degradation rate of Zn alloys and influence cytocompatibility. ZnMg1Ca0.1 alloy showed the highest adhesion density of bone marrow-derived mesenchymal stem cells (BMSCs) because the degradation rate of ZnMg1Ca0.1 alloy could supply appropriate pH and [Zn2+] for BMSCs. Mg addition could improve the cytocompatibility of ZnMgCa alloys. However, a Mg content threshold was observed, and the Mg content should be exactly controlled. Combined with the mechanical properties, the degradation rate of zinc alloy implants could be adjusted to match the healing of tissues by adding Mg. In vivo results showed that the degradation rate of the optimized ZnMgCa alloy could match the healing of local tissues or organs. Animal implant results revealed alloy safety.

Tribocorrosion performance of Zn, Zn[sbnd]Ni with magnesium electrodeposited on medium carbon steel in a chloride environment

The damage of materials due to both wear and corrosion has a significant impact on engineering systems. Therefore, the industry has recently been more focused on the life cycle costs of the systems and has sought to improve reliability. The reliability and efficiency of machines and equipment depend on tribocomponents operating in a chloride environment. Crucial components are subjected to a wide range of devastating tribocorrosion effects, and in many operations combined with mechanical loadings.A number of protection systems to mitigate corrosion in the marine environment have been employed to counter these problems. One of them are electrodeposited coatings such as Zn and ZnNi which were documented in numerous research. Much of it has been conducted in areas of corrosion behavior, mechanical properties, and tribology. In order to enhance the corrosion resistance of zinc film, various metals have been implemented. One of them is magnesium. The influence of Mg content in the alloy on the corrosion resistance has been noted by many researchers. However, one cannot find recent scientific publications and papers presenting tribocorrosion performance of Zn-Ni-Mg alloy coatings. Therefore, tribocorrosion behavior of ZnNi alloy coating with magnesium was investigated.The main aim of this study is to investigate tribocorrosion performance of Zn, and Zn-Ni-Mg alloys coatings with a possibility to replace Zn coating in engineering systems. All coatings were provided on AISI 1045 medium carbon steel with trivalent chrome passivation. The study was carried out in a ball-on-plate combination in 3.5% solution of NaCl. A triple electrode system with a precision four-channel ATLAS 9833 potentiostat was used for monitoring the electrochemical phenomena. The reference electrode was a calomel electrode, SCE. Polarization curves for all samples in 3.5% NaCl were utilized. The evaluation of the surface wear of all samples with coatings was done. The measure of the wear was the depth of the wear trace which was defined on the basis of profilometric measurements. The value of hardness of coatings was identified.

Studying the Influence of Mg Content on the Microstructure and Associated Localized Corrosion Behavior of Zn-Mg PVD Coatings Using SVET-TLI

Physical vapour deposited (PVD) zinc and zinc-magnesium coatings are compared to commercial galvanized zinc and zinc-magnesium-aluminum coatings in terms of bare metal corrosion when immersed in chloride-containing solution. A scanning vibrating electrode technique has been augmented to capture photographic images, in-situ, which complement the spatially and temporally resolved electrochemical data by providing visual evidence of corrosion events and their subsequent stabilization or propagation over the surface. Hot dip galvanized zinc coatings demonstrate heterogeneous localized corrosion behavior, contrary to the general corrosion of the PVD pure zinc layer. The PVD coating containing 4 wt% magnesium has a discrete microstructure much finer than the structure of hot dip zinc-magnesium-aluminum coatings, which results in smaller and more abundant anodic features. Increasing the magnesium content in PVD zinc-magnesium to 10 wt% coatings increases the relative size of the anodic events and reduces the number observed accordingly. A further increase in magnesium content to 20 wt% sees a reduction in anode size and evidence of de-activation during the experiment. A clear correlation between magnesium content and the intensity of characteristic staining on the PVD coatings is also observed.

Influence of Mg content on ageing precipitation behavior of Al-Cu-Li-x alloys

The addition of minor Mg (~0.4 wt%) to Al-Cu-Li alloy could not only modify the precipitation path but also promote the precipitation of T1 (Al2CuLi) phase, however, the influence of higher Mg addition on the microstructures during ageing is still not clear. In this work, the influence of high Mg addition (>0.4 wt%) on the precipitation sequence, precipitation kinetics and the corresponding strengthening of an Al-Cu-Li alloy has been investigated by atom probe tomography (APT), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and tensile testing. For an Al-Cu-Li-0.4 wt% Mg alloy in the peak-aged condition, the microstructure contains a high density of fine T1 precipitates along with some non-negligible θ' phase (Al2Cu). When adding larger amount of Mg (0.8 wt%) to the alloy, however, the precipitation of S′ phase (Al2CuMg) is strongly accelerated at the expense of T1 and θ' phases. Much more Mg clusters are observed by APT at the early ageing stages of the high Mg-containing alloy, leading to more rapid hardening response. The precipitation kinetics for T1 phase become somewhat sluggish due to decreased nucleation sites and shortage of available solutes caused by formation of more S′ precipitates. The precipitation of coarse T1 and S′ phases is significantly detrimental to the ductility and toughness in the peak-aged condition for the high Mg-containing alloy.

The structural, microstructural and thermoelectric properties of Mg2Si synthesized by SPS method under excess Mg content conditions

The aim of the study was to determine the influence of Mg excess on the physicochemical properties with particular emphasis on thermoelectric properties of synthesized Mg2Si. Available literature devoted to this issue suggests very often a need to use an excess of Mg during the synthesis process in order to obtain homogeneous material [1–13]. Samples with 0–10 wt% of excessive Mg were prepared using the Spark Plasma Sintering (SPS) method. The structural and phase compositions were examined using X-ray diffraction XRD and scanning electron microscopy SEM coupled with EDS detector for the chemical composition analysis. The influence of Mg content on the impedance spectrum and transport properties, i.e.: electrical conductivity, the Seebeck coefficient and the thermal conductivity was studied in temperature range from 300 to 720 K. Carrier concentration was measured using Hall method. Scanning thermoelectric microprobe (STM) was used to determine the uniformity of Seebeck coefficient. Furthermore, the temperature dependences of the thermoelectric figure of merit ZT were calculated. The experiments performed, allow concluding that Mg excess which is in liquid phase during the sintering process gathers mostly at the grain boundaries, enhancing sintering process and decreasing total porosity of the samples. Moreover, higher Mg content increases electrical and thermal conductivity of Mg2Si, what causes simultaneous decrease of Seebeck coefficient. Step change in the electrical conductivity between the samples without and with the excess of magnesium (e.g. σ = 30 S m−1 for 0 wt% and σ = 1.26 · 105 S m−1 for 10 wt%) indicates the presence of a percolating mechanism.

Effects of Mg Content on the Fatigue Strength and Fracture Behavior of Al-Si-Mg Casting Alloys

In order to investigate the influence of Mg content on the fatigue properties in Al-Si-Mg alloy, uniaxial tensile tests and rotating bending fatigue tests were conducted on two Al-7Si-Mg casting alloys, with different Mg contents of 0.3 and 0.6 wt.%. The fracture surfaces of the specimens were observed by scanning electron microscopy, and the fatigue crack growth process was obtained by the replica method. The results indicate that the increase in Mg content enhances the yield strength and tensile strength of the alloy, whereas it reduces its elongation. There is an obvious knee point in the S–N curves of Al-7Si-0.6Mg alloy while that of Al-7Si-0.3Mg alloy shows continuous decrease. The fatigue strength at 5 × 105 cycles is 60 MPa for Al-7Si-0.3Mg alloy and 80 MPa for Al-7Si-0.6Mg alloy. For the two types of specimens, the fatigue failure can initiate from crystal slip and casting defects. The replica results suggest that cracks in Al-7Si-0.6Mg alloy grow more slowly than that in Al-7Si-0.3Mg alloy.

P-1.7: Influence of Mg Content and Argon/Oxygen Ratio on Photoelectric properties of co-sputtering MIZO

The authors investigated optical and electrical properties of MIZO film which was prepared by co-sputtering for the first time. MgO and IZO (In:Zn=9:1) were used as the two targets to sputter at the same time. By controlling the sputtering power of the two targets, the content of Mg, resistivity and the optical band gap of MIZO can be adjusted, thereby meeting the needs of the applications of UV detector and other purposes. With the increasing of Mg content, the resistivity of MIZO increased from 9.1× 10−4 Ωcm to 6.0 × 108 Ωcm, and the band gap could be broadened to 3.97eV. Except for Mg content, the effect of the ratio of argon to oxygen was also explored, IZO as one of the two targets is very sensitive to the ratio of argon to oxygen, leading to the decrease of the MIZO resistivity of the same magnesium content with the increase of the ratio of argon to oxygen, while the band gap increases first and then decrease.