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1.
Wenlong Xiao Shusheng Jia Lidong Wang Yaoming Wu Limin Wang 《Journal of Alloys and Compounds》2009,480(2):L33-L36
The microstructures and mechanical properties of cast Mg–Zn–Al–RE alloys with 4 wt.% RE and variable Zn and Al contents were investigated. The results show that the alloys mainly consist of α-Mg, Al2REZn2, Al4RE and τ-Mg32(Al,Zn)49 phases, and a little amount of the β-Mg17Al12 phase will also be formed with certain Zn and Al contents. When increasing the Zn or Al content, the distribution of the Al2REZn2 and Al4RE phases will be changed from cluster to dispersed, and the content of τ-Mg32(Al,Zn)49 phase increased gradually. The distribution of the Al2REZn2 and Al4RE phases, and the content of β- or τ-phase are critical to the mechanical properties of Mg–Zn–Al–RE alloys. The Mg–6Zn–5Al–4RE alloy with cluster Al2REZn2 phase and low content of β-phase, exhibits the optimal mechanical properties, and the ultimate tensile strength, yield strength and elongation are 242 MPa, 140 MPa and 6.4% at room temperature, respectively. 相似文献
2.
Myoung Youp Song Chang-Dong Yim Jong-Soo Bae Daniel R. Mumm Seong-Hyeon Hong 《Journal of Alloys and Compounds》2008,463(1-2):143-147
Mg–23.5 wt.%Ni–(5, 10 and 15 wt.%)La alloys were prepared by gravity casting and their hydrogen-storage properties were examined after pulverizing. The gravity cast Mg–23.5Ni–(5, 10 and 15)La alloys consist of α-Mg, Mg2Ni and Mg17La2 phases. The activated Mg–23.5Ni–10La alloy has the highest hydrogen-storage capacity of 4.96 wt.%H (from P–C–T curve) and the highest initial hydriding rate (hydrogen content 3.83 wt.%H at 10 min) with an initial hydrogen pressure in the channel of 11 bar H2 at 573 K. This is attributed to its containing the largest amount of the Mg17La2 phase, which is easily dissociable during the hydriding reaction. 相似文献
3.
In order to improve the non-uniform corrosion of Al–0.5Zn–0.03In–1Mg–0.05Ti alloys, Al–5Zn–0.03In–1Mg–0.05Ti–xLa (x = 0.3, 0.5 and 0.7 wt.%) alloys were developed. Microstructures and electrochemical properties of the alloys were investigated. The results show that the optimal microstructures and electrochemical properties are obtained in Al–5Zn–0.03In–1Mg–0.05Ti–0.5La alloy. The main precipitate phase is Al2LaZn2 particles. The excellent electrochemical properties of Al–5Zn–0.03In–1Mg–0.05Ti–0.5La alloy is mainly attributed to fine grains and grain boundaries containing fine Al2LaZn2 precipitates. At the same time the fine grains can improve the non-uniform corrosion of Al–0.5Zn–0.03In–1Mg–0.05Ti alloy. 相似文献
4.
Daisuke Kyoi Tetsuo Sakai Naoyuki Kitamura Atsushi Ueda Shigeo Tanase 《Journal of Alloys and Compounds》2008,463(1-2):311-316
Magnesium-based hydrides with Zr or Hf have been synthesized by means of an ultra-high pressure technique. Powder mixtures of MgH2 and ZrH2 or HfH2 have been heated up to 873 K under 4–8 GPa in a multi-anvil cell. New ternary phases (Mg–Zr–H and Mg–Hf–H) with a face centered cubic (FCC) structure have been formed. In the Mg–Zr hydride, the FCC phase with disordered metal–atom occupancy was observed, while a Ca7Ge-type super-lattice structure was observed in the Mg–Hf hydride. By the temperature programmed desorption (TPD) measurements, these new hydrides exhibit the hydrogen-desorption at around 543–583 K, which were 130–70 K lower than that of MgH2 at a heating rate of 10 K/min under vacuum. Desorbed hydrogen contents were estimated to be 4.2 and 3.0 mass% for Mg–Zr and Mg–Hf hydrides, respectively. 相似文献
5.
Z.I. Ortiz P. Díaz-Arista Y. Meas R. Ortega-Borges G. Trejo 《Corrosion Science》2009,51(11):2703-2715
The morphology, composition, phase composition and corrosion products of coatings of pure Zn (obtained from two types of electrolytic bath: an acidic bath (Znacid) and a cyanide-free alkaline bath (Znalkaline)) and of Zn–Mn and Zn–Co alloys on steel substrates were studied. To achieve this, diverse techniques were used, including polarization curves, atomic force microscopy (AFM), scanning electron microscopy (SEM), glow discharge spectroscopy (GDS), X-ray diffraction (XRD), and the salt spray test. In the salt spray test, the exposure time required for the coatings to exhibit red corrosion (associated with the oxidation of steel) decreased in the following order: Zn–Mn(432h) > Zn–Co(429h) > Znalkaline(298h) > Znacid(216h). The shorter exposure times required for corrosion of the pure Zn coatings are related to the coating composition and the crystallographic structure. Analysis of the corrosion products disclosed that Zn5(OH)8Cl2·H2O was a corrosion product of all of the coatings tested. However, the formation of oxides of manganese (MnO, Mn0.98O2, Mn5O8) in the Zn–Mn coating, and the formation of the hydroxide Zn2Co3(OH)10·2H2O in the Zn–Co coating, produced more compact and stable passive layers, with lower dissolution rates. 相似文献
6.
Xin Zhang Dmytro Kevorkov In-Ho Jung Mihriban Pekguleryuz 《Journal of Alloys and Compounds》2009,482(1-2):420-428
Three isopleths at the Mg-rich corner of Mg–Mn–Ce ternary system were investigated via thermal analysis, SEM/EPMA and XRD. A ternary eutectic reaction was observed at 1 wt.% Mn and 23 wt.% Ce and 592 °C. A solid-solution type ternary intermetallic compound, (Mg,Mn)12Ce, was observed with 0.5 at% solid solubility of Mn in the tetragonal Mg12Ce. With the aid of thermodynamic modeling and experiments, a revised phase diagram for the binary Mg–Ce system and the isopleths of 0.6, 1.8 and 2.5 wt.% Mn were proposed up to 25 wt.% Ce. 相似文献
7.
Chunmei Liu Jianhua Wang Fucheng Yin Zhi Li Xuping Su 《Journal of Alloys and Compounds》2009,482(1-2):213-218
Following up on recent studies of the isothermal section of the Zn–Fe–Ni, Zn–Fe–Bi and Zn–Bi–Ni ternary systems at 450 °C, the Zn-rich corner of the 450 °C isothermal section of the Zn–Bi–Fe–Ni quaternary system with the Zn being fixed at 93 at.% was determined experimentally using the equilibrated alloys approach. The specimens were investigated by means of scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). It was found there exist 4 two-phase regions, 5 three-phase regions and 2 four-phase regions. Two liquid L (Zn) and L (Bi) can coexist with T, ζ and δ-Ni in this isothermal section, no new phase was found in this study. 相似文献
8.
Atsushi Yamaga Kiyohide Hibino Masanori Suzuki Masaaki Yamada Kazuhide Tanaka Kazuyuki Ueda 《Journal of Alloys and Compounds》2008,460(1-2):36-40
Hydrogen distribution and behavior on a Mg–Ni alloy surface are studied by using a time-of-flight electron-stimulated desorption (TOF-ESD) microscopy and a scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX). The desorbed hydrogen ions are energy-discriminated and distinguished into two characters in the adsorbed states, which belong to Mg2Ni grains and the other to oxygen-contaminated Mg phase at the grain boundaries. Adsorbed hydrogen is found to be stable up to 150 °C, but becomes thermally unstable around at 200 °C. 相似文献
9.
The effect of Zn additions (0, 1 and 2 wt%) on the microstructure and phase formation of Mg–5Gd alloy has been investigated using X-ray diffraction (XRD), differential thermal analyzer (DTA) and scanning electron microscope (SEM) techniques. Zinc free alloy shows the negligible amount of Mg5Gd phase formation whereas 1 wt% Zn addition leads to formation of more volume of Mg5Gd phase having dissolution temperature at 518 °C. Two weight percentage of Zn addition yielded more volume of MgZn2 phase having the dissolution temperature at 333 °C but less volume of Mg5Gd phases. Moreover, 1 wt% Zn addition is found to be more favorable to the age hardening behavior as compared to 2 wt% Zn added alloy. 相似文献
10.
The formation and the growth of the intermetallic compounds (IMCs) at the interface between the Sn–8Zn–3Bi–xAg (x = 0, 0.5, and 1 wt.%) lead-free solder alloys and Cu substrate soldered at 250 °C for different durations from 5 to 60 min were investigated. It was found that Cu5Zn8 and CuZn5 formed at Sn–8Zn–3Bi/Cu interface, and Cu5Zn8 and AgZn3 formed at the solder/Cu interface when the solder was added with Ag. The thickness of IMC layers in different solder/Cu systems increased with increasing the soldering time. And the growth of the IMCs was found to be mainly controlled by a diffusion mechanism. Additionally, the growth of the IMC layers decreased with increasing content of Ag in the soldering process. 相似文献
11.
J.A. Puszkiel P. Arneodo Larochette F.C. Gennari 《Journal of Alloys and Compounds》2008,463(1-2):134-142
The transition metal complex hydride Mg2FeH6 has been successfully synthesized utilizing mechanical milling of a 2Mg–Fe mixture followed by heating at 673 K under 6 MPa of hydrogen pressure, without pressing step. The obtained yield of Mg2FeH6 was about 50%. Hydrogen storage properties of the Mg–Fe–H system, i.e. capacities, absorption/desorption kinetics and thermodynamic parameters, were examined. The pressure-composition isotherm (PCI) measurements of the samples at 548–673 K showed that the alloys possessed good cyclic stability and reversibility. Enthalpies and entropies of decomposition of the Mg–Fe–H system were evaluated by van’t Hoff plots. The absorption/desorption rates at 573 K were very fast in comparison with the reported data. The non-isothermal desorption of hydrogen was found greatly dependent on the thermal history of the sample. 相似文献
12.
The synthesis process of Mg–Ti alloys with a BCC (body centered cubic) structure by means of ball milling was studied by X-ray diffraction and various microscopic techniques. The morphology and crystal structure of Mg–Ti alloys changed with increase of milling time. During ball milling of Mg and Ti powders in molar ratio of 1:1, firstly, plate-like particles stuck on the surface of the milling pot and balls. After these plate-like particles fell off from the surface of the milling pot and balls, spherical particles with the mean diameter of 1 mm, in which concentric layers of Mg and Ti were disposed, were formed. These spherical particles were crushed into spherical particles with the diameter of around 10 μm by introduction of cracks along the boundaries between Mg and Ti layers. Finally, the Mg50Ti50 BCC phase with the lattice parameter of a = 0.342(1) nm and the grain size of 3 nm was formed. During milling of Mg and Ti to synthesize the BCC alloy, Mg and Ti were deformed mainly by the basal plane slip and the twinning deformation, respectively. Ti acted as abrasives for Mg which had stuck on the surface of the milling pot and balls. The BCC phase was found after Mg dissolved in Ti. 相似文献
13.
Hui-Yuan Wang Min Zha Bo Liu Dong-Ming Wang Qi-Chuan Jiang 《Journal of Alloys and Compounds》2009,480(2):L25-L28
The microstructural evolution behavior of Mg–5Si–1Al alloys modified with Sr–Sb during isothermal heat treatment was investigated in the present study. Although the morphology of eutectic Mg2Si phase varied with isothermal holding temperature increasing from 620 to 670 °C, no spheridization occurred for primary Mg2Si polyhedrons in Sr–Sb-modified alloy even when the temperature reaches 660 or 670 °C. Such an abnormal phenomenon of primary Mg2Si, during partial remelting isothermal treatment, might be ascribed to both the spheridization restriction effect caused by incorporation of Sb in Mg2Si and stability of octahedral primary Mg2Si crystals faced by {1 1 1} planes. 相似文献
14.
A series of Al–Ni–Co alloys forming stable decagonal (D-ANC) quasicrystals was studied in as-cast and annealed states. It was shown that under certain conditions periodic structures with pseudodecagonal (PD) symmetry can be produced at the same compositions as stable decagonal quasicrystals. Different variants of D-ANC and PD were observed in a compositional range of 70–72.5 at.% Al and 13–18 at.% Co. As-cast D-ANC can be transformed to single-phase PD of the same local composition. Single-phase PDs can be transformed to D-ANC of the same composition by heating to a temperature higher than the formation temperature of these PDs. The transition between PD and D-ANC was studied in more detail in Al71Ni14.5Co14.5 and Al70Ni15Co15 by electron microscopy, powder X-ray diffractometry and differential thermal analysis. The results of this study do not confirm the thermodynamic stability of this PD structure. 相似文献
15.
The mechanical properties of hydrogenated Mg–Al magnesium alloys with various aluminum content were investigated. The ductility, yield strength (YS) and ultimate tensile strength (UTS) of the hydrogenated material decreased while the hardness increased with increasing the aluminum content. Microscopic observations of cross-sections of hydrogenated specimens with various Al content revealed that hydrogen cracks extended deeply as the Al content in the Mg–Al alloys increased. Moreover, X-ray diffraction (XRD) analysis revealed that MgH2 and AlH3 hydrides are formed during hydrogenation and were found to contribute to hydrogen embrittlement of Mg–Al alloys. However, the embrittled zone was observed to be larger at the fracture surface of Mg–15Al alloy than that of Mg–5Al alloy. Moreover, the fracture surface of Mg–30Al alloy exhibited completely brittle fracture after hydrogenation. 相似文献
16.
Age hardening phenomena of rapidly quenched non-combustible Mg−Al−Si−Ca and Mg−Zn−Ca alloys 总被引:1,自引:0,他引:1
Won-Wook Park Bong-Sun You Byoung-Gi Moon Jung-Gyu Park Sung-Chul Yang 《Metals and Materials International》2001,7(1):9-13
Non-combustible Mg−Al−Si and Mg−Zn base alloys containing Ca were rapidly quenched via melt spinning. The melt-spun ribbons
were aged, and then the effects of additional elements on age hardening behavior and microstructural change were investigated.
Age hardening occurred after aging at 200°C in the Mg−Al−Si−Ca alloys mainly due to the formation of Al2Ca or Mg2Ca phases, whereas it occurred in the Mg−Zn−Ca alloys mostly due to the distribution of Mg6Ca2Zn3 and Mg2Ca. With the increase of Ca content, the hardness values of the aged ribbons were increased. In this study, Mg−6Zn−5Ca alloy
showed the maximum peak hardness after aging at 200°C for 1 hour. On the contrary, Mg−xZn−1.5Ca alloys couldn't show the pronounced
peak hardness because of low Ca content. 相似文献
17.
The influence of Si on the corrosion behaviour of Al–5Zn–0.03In–1Mg–0.05Ti (wt.%) alloy was investigated by the microstructure observation and electrochemical measurements in order to improve its corrosion non-uniform and electrochemical properties. The main precipitates in Al–5Zn–0.03In–1Mg–0.05Ti–0.1Si (wt.%) alloy is Mg2Si phase, which decrease the galvanic corrosion because the potential difference between Mg2Si and a-Al is smaller than that between MgZn2 and a-Al. The addition of Si improves the corrosion uniformity of the anode due to the fine equiaxed grains and grain boundaries where Mg2Si particles uniformly distributed. The results indicate that the microstructure, electrochemical characteristics and corrosion uniformity can be improved significantly after adding 0.1 wt.% Si into Al–5Zn–0.03In–1Mg–0.05Ti (wt.%) alloy. 相似文献
18.
A.C.F.M. Costa D.A. Vieira V.J. Silva V.C.S. Diniz R.H.G.A. Kiminami L. Gama 《Journal of Alloys and Compounds》2009,483(1-2):37
This work reports the preparation of Ni–Zn–Sm ferrite powders by combustion reaction using microwaves energy and XRD characterization. The influence of the fuel type used was investigated. The metallic nitrates and fuels (urea, glycine or 1:1 mixture) were heated in microwave oven for 5 and 10 min using the power of 450 and 630 W. Ni–Zn–Sm ferrite and traces of secondary phases were observed in the powders obtained with glycine and mixture (1:1). The powers obtained with urea presented low cristallinity, only the main peak of the Ni–Zn–Sm ferrite phase was observed. 相似文献
19.
A part of the Al–Pd–Mn phase diagram in the vicinity of the icosahedral phase was refined. Partial isothermal sections of 710, 850, 870 and 880°C are presented. The overall compositional range of the icosahedral phase was found to be between 5.8 and 10.5 at.% Mn and between 69.5 and 71.5 at.% Al at these temperatures. It shifts to lower Mn concentration at lower temperatures. It was confirmed that the phase usually designated Al3Pd has a lower Al concentration in the binary alloys than that according to the formula. It extends to the ternary compositions up to about 5 at.% Mn. The increase of the Mn content results in an increase of the Al concentration of this phase. 相似文献
20.
The phase relations in the ternary system Yb–Zn–In have been established for the partial isothermal section in the 0–33.3 at.% ytterbium concentration range at 400 °C, by researching of more than forty alloys. X-ray powder diffraction (XRPD), optical microscopy (OM) and scanning electron microscopy (SEM), complemented with energy dispersive X-ray spectroscopy (EDS), were used to study the microstructures, identify the phases and characterize their crystal structures and compositions. The phase equilibria of this Yb–Zn–In partial section at 400 °C are characterized by the presence of three extended homogeneity ranges, indium solubility in Yb13Zn58 and YbZn2 and of zinc solubility in YbIn2, and the existence of one ternary intermetallic compound, YbZn1−xIn1+x, x = 0.3. This new compound crystallizes in the UHg2 structure type (space group P6/mmm), with a = 4.7933(5) Å, c = 3.6954(5) Å. The studied partial isothermal section has eight ternary phase fields at 400 °C. 相似文献