scholarly journals The Study of A New Symmetrical Rod Phase in Mg-Zn-Gd Alloys

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 988
Author(s):  
Yue ◽  
Feng ◽  
Wu ◽  
Zhou ◽  
Zuo ◽  
...  
Keyword(s):  
Ternary Phase ◽  
Eutectic Structure ◽  
New Materials ◽  
Casting Method ◽  
Scanning Calorimetry ◽  
Specific Strength ◽  
High Specific Strength ◽  
Eds Analysis ◽  
Lamellar Eutectic Structure ◽  
Better Than

Quasicrystal alloys have a wide application prospect because of excellent performances and characteristics; meanwhile, magnesium alloys are known as green engineering materials because of their high specific strength and light weight. Therefore, the study of Mg-Zn-Gd quasicrystal alloys is of great significance for the development of new materials. In this paper, Mg(70-x)Zn30Gdx(x=3,4,5) alloys were prepared by a conventional casting method and the morphologies and properties of these alloys were studied. There was a new symmetrical rod phase found in the Mg66Zn30Gd4 alloy and the symmetrical rod phase was identified as a ternary phase by mapping scanning and energy dispersive spectroscopy (EDS) analysis. The Zn/Gd ratio of the symmetrical rod phase was found to be 4.8 and the TEM images obtained were different from the typical diffraction spots patterns of quasicrystalline, which means it is unlikely to be quasicrystalline. With different melt holding time, the symmetrical rod phase evolved gradually over time from a lamellar eutectic structure; differential scanning calorimetry (DSC), heat treatment, and microhardness tests showed that the melting temperature of the rod phase was 453 °C and that its thermal stability and microhardness are better than quasicrystalline. Hence, the symmetrical rod phase is a new kind of complex metallic alloy phase whose composition and properties are close to those of quasicrystals but is not quasicrystalline.

A Brief Review about Surface Treatment of Magnesium Alloys

2012 ◽  
Vol 724 ◽  
pp. 307-310 ◽  
Author(s):  
Yu Bai ◽  
Fang Li Yu ◽  
Jun Du ◽  
Wen Xian Wang ◽  
Ze Qin Cui ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Protective Coatings ◽  
Corrosion And Wear ◽  
New Materials ◽  
Paper Briefly ◽  
Effective Protection ◽  
Widespread Application ◽  
Specific Strength ◽  
Aerospace Applications ◽  
High Specific Strength

Due to the low density and high specific strength, magnesium and its alloys have been extensively used in the automobile and aerospace applications, where the weight reduction is critical. However, they are highly prone to corrosion, which has greatly limited their application in the automotive and aerospace industries. This paper briefly reviews the technologies for improving the corrosion and wear resistance of magnesium alloys and finds that the widespread application of magnesium alloys is still limited by the lack of proper protective coatings. Therefore, there is still a need to explore new materials and methods for the effective protection of magnesium and its alloys.

scholarly journals Experimental Study on Tribological Characteristics of AA 6061 Alloy Reinforced with Al2O3 and B4C Particles

2018 ◽  
Vol 24 (6) ◽  
pp. 1
Author(s):  
Khansa Daood AlShamari ◽  
Ihsan Kadhom AlNaimi ◽  
Raad Hameed Majid
Keyword(s):  
Hardness Test ◽  
Ceramic Materials ◽  
Stir Casting ◽  
Casting Method ◽  
Specific Strength ◽  
High Specific Strength ◽  
Pin On Disc ◽  
B4c Particles ◽  
Automotive Parts ◽  
Marine Applications

Two different composite materials were prepared by stir casting method of AA 6061 alloy as a matrix reinforced with two addition different ceramic materials Al2O3 and B4C of grain size   20 µm by 2.5, 5, 7.5 and10% in weight. The composite material with aluminum alloy as a matrix possesses a unique mechanical properties such as: high specific strength and hardness, low density, and high resistance to corrosion and friction wear. This composite is widely used in automotive parts space and marine applications. Pin-on-disc technique was used to calculate the wear rate for each addition of Al2O3 and B4C particles. Rockwell hardness test and optical micrographs examinations were carried out to analyze, compare, and evaluate the addition of reinforced particles. The results of this investigation appeared that the 7.5% of ceramic particles addition give highest values of the hardness and wear resistance.      

A New Periodic Cellular Metal With Kagome Trusses and Its Performance

Aerospace ◽  
2006 ◽  
Author(s):  
Yong-Hyun Lee ◽  
Ji-Eun Choi ◽  
Ki-Ju Kang
Keyword(s):  
Raw Materials ◽  
Future Market ◽  
New Materials ◽  
Specific Strength ◽  
Cellular Metal ◽  
High Specific Strength ◽  
New Type ◽  
Strength And Stiffness ◽  
Metal Wires ◽  
Very High

Periodic cellular metals (PCM), especially truss PCM's seem promising as new materials in 21 century. Various works have been performed for the mechanical and thermal performance. However, only a number of papers have been published regarding fabrication techniques of PCM, even though the techniques should determine whether PCM's is survived in the future market, or not. In this work a new type of PCM with Kagome trusses is presented. Continuous metal wires as the raw materials are assembled in six directions with least deflection, which gives very high specific strength and stiffness. The mechanical behavior under compression and bending of hand-made specimens is presented. Also, the benefits and features are discussed.

The Influence of Eutectic Morphology on the Impact Properties of High Pressure Die Cast Mg-Rare-Earth Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 683-686 ◽  
Author(s):  
Mark Easton ◽  
Katharina Strobel ◽  
Su Ming Zhu ◽  
Mark A. Gibson ◽  
Jian Feng Nie
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Eutectic Structure ◽  
Rare Earth Alloys ◽  
Impact Properties ◽  
Die Cast ◽  
Eutectic Morphology ◽  
The Impact ◽  
Lamellar Eutectic Structure ◽  
Better Than

The impact properties of high-pressure die cast Mg-RE alloys were investigated. It was found that, for rare earth contents between 2-4 wt.%, the Mg-La and Mg-Nd alloys performed better than the Mg-Ce alloys in un-notched tests. The notched results appear to be related to the amount of intermetallic. In contrast, the un-notched results indicate that at some compositions the Mg-La alloys out-performed the other alloys when compared to the amount of intermetallic. It was apparent that a lamellar eutectic structure can improve the un-notched impact properties of Mg-RE based alloys even when this is not evidenced in tensile test or notched impact results.

Precipitation in Al-Li-Cu Alloys

1981 ◽  
Vol 39 ◽  
pp. 44-45
Author(s):  
J. E. O'Neal ◽  
K. K. Sankaran
Keyword(s):  
Electron Microscopy ◽  
Age Hardening ◽  
Precipitation Behavior ◽  
Zone Formation ◽  
Specific Strength ◽  
Hardening Behavior ◽  
Cu Alloys ◽  
High Specific Strength ◽  
Transmission Electron ◽  
Structural Applications

Al-Li-Cu alloys combine high specific strength and high specific modulus and are potential candidates for aircraft structural applications. As part of an effort to optimize Al-Li-Cu alloys for specific applications, precipitation in these alloys was studied for a range of compositions, and the mechanical behavior was correlated with the microstructures.Alloys with nominal compositions of Al-4Cu-2Li-0.2Zr, Al-2.5Cu-2.5Li-0.2Zr, and Al-l.5Cu-2.5Li-0.5Mn were argon-atomized into powder at solidification rates ≈ 103°C/s. Powders were consolidated into bar stock by vacuum pressing and extruding at 400°C. Alloy specimens were solution annealed at 530°C and aged at temperatures up to 250°C, and the resultant precipitation was studied by transmission electron microscopy (TEM).The low-temperature (≲100°C) precipitation behavior of the Al-4Cu-2Li-0.2Zr alloy is a combination of the separate precipitation behaviors of Al-Cu and Al-Li alloys. The age-hardening behavior at these temperatures is characteristic of Guinier-Preston (GP) zone formation, with additional strengthening resulting from the coherent precipitation of δ’ (Al3Li, Ll2 structure), the presence of which is revealed by the selected-area diffraction pattern (SADP) shown in Figure la.

scholarly journals Microstructural Characterization and Mechanical Property of Al-Li Plate Produced by Centrifugal Casting Method

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 966
Author(s):  
Qingle Tian ◽  
Kai Deng ◽  
Zhishuai Xu ◽  
Ke Han ◽  
Hongxing Zheng
Keyword(s):  
Centrifugal Casting ◽  
High Strength ◽  
Microstructural Characterization ◽  
Fracture Morphology ◽  
Total Elongation ◽  
Mechanical Anisotropy ◽  
Tensile Fracture ◽  
Casting Method ◽  
Scanning Calorimetry ◽  
Strengthening Phases

Using a centrifugal casting method, along with deformation and aging, we produced a high-strength, low-anisotropy Al-Li plate. The electron probe microanalysis, transmission electron microscope, differential scanning calorimetry, and X-ray diffraction were used to clarify the evolution of strengthening phases. Experimental results showed that centrifugal-cast Al-Li plate consisted of intragrain δ′—(Al,Cu)3Li precipitate and interdendritic θ′—Al2Cu particles. After cold-rolling to a reduction ratio of 60% and annealing at 800 K for 90 min, both primary θ′ and δ′ were dissolved in solid solution. Aging at 438 K for 60 h led to the formation of two kinds of precipitates (needle-like T1—Al2CuLi and spherical δ′ in two sizes), which acted as the main strengthening phases. The average values of ultimate tensile strength and yield strength for the anneal-aged plate reached 496 MPa and 408 MPa, with a total elongation of 3.9%. The anneal-aged plate showed mechanical anisotropy of less than 5%. The tensile fracture morphology indicated a typical intergranular fracture mode.

Microstructural Evolution in Al-Ti Multilayered Film with Annealing

1999 ◽  
Vol 5 (S2) ◽  
pp. 836-837
Author(s):  
R. Mitra ◽  
W.A. Chiou ◽  
A.Madan ◽  
R. Hoffman ◽  
J.R. Weertman
Keyword(s):  
Magnetron Sputtering ◽  
Ingot Metallurgy ◽  
Multilayered Film ◽  
Multilayered Structures ◽  
Multilayered Films ◽  
Specific Strength ◽  
The Past ◽  
High Specific Strength ◽  
Significant Interest ◽  
Deposited Film

There has been a significant interest in the development of dispersion-hardened aluminum for many years for high specific strength and modulus. Such materials are usually processed by powder or ingot metallurgy routes. In this study, Al3 Ti dispersion hardened Al was obtained by annealing Al-Ti multilayers. Al-Ti multilayered films have been characterized in the past by observing the structure of the layers, as well as tensile properties and hardness. This paper reports the structure of Al-Ti multilayers and the evolution of matrix and dispersoid microstructure on annealing.The Al-Ti multilayered structures were prepared by magnetron sputtering using Al and Ti as targets and either Si (100) or NaCl as substrates. The bi-layer thickness was maintained around 16 nm with Ti constituting 12% of the total. The substrate was alternately moved below the Al and Ti targets for the purpose of deposition. The as-deposited film on the substrate and NaCl salts were annealed at 400°C for periods between 1 and 24 h in a vacuum (10−5 torr) furnace.

scholarly journals Materials for Automotive Lightweighting

2019 ◽  
Vol 49 (1) ◽  
pp. 327-359 ◽  
Author(s):  
Alan Taub ◽  
Emmanuel De Moor ◽  
Alan Luo ◽  
David K. Matlock ◽  
John G. Speer ◽  
...  
Keyword(s):  
Galvanic Corrosion ◽  
Low Carbon Steel ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
New Materials ◽  
Specific Strength ◽  
Advanced High Strength Steels ◽  
Strength And Stiffness ◽  
The Cost

Reducing the weight of automobiles is a major contributor to increased fuel economy. The baseline materials for vehicle construction, low-carbon steel and cast iron, are being replaced by materials with higher specific strength and stiffness: advanced high-strength steels, aluminum, magnesium, and polymer composites. The key challenge is to reduce the cost of manufacturing structures with these new materials. Maximizing the weight reduction requires optimized designs utilizing multimaterials in various forms. This use of mixed materials presents additional challenges in joining and preventing galvanic corrosion.

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