Corrosion performance of magnesium (Mg) alloys containing rare-earth (RE) elements

2013 ◽  
pp. 38-60 ◽  
Author(s):  
J. Meng ◽  
W. Sun ◽  
Z. Tian ◽  
X. Qiu ◽  
D. Zhang
Keyword(s):  
Rare Earth ◽  
Mg Alloys ◽  
Corrosion Performance ◽  
Re Elements

Investigation and Application of Excellent Performance Mg Rare Earth Alloys as a Structural Material

2007 ◽  
Vol 539-543 ◽  
pp. 1719-1722 ◽  
Author(s):  
Li Min Wang ◽  
Qiu Ming Peng ◽  
Jie Yang ◽  
Da Qing Fang ◽  
Yao Ming Wu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Structural Material ◽  
Creep Resistance ◽  
Mg Alloys ◽  
Rare Earth Alloys ◽  
Excellent Performance ◽  
Specific Strength ◽  
High Specific Strength ◽  
Transmission Case ◽  
Re Elements

Magnesium (Mg) alloys are becoming one of the key engineering materials for aerospace and automotive industries because of their low density, high specific strength, excellent machinability and good diecastability, etc. In the meantime, conventional Mg alloys are limited for their low strength and creep resistance. Therefore, special attention is given on its applications at high temperature such as the transmission case and the engine block, In the near decades, much effort have been devoted to improving the properties such as strength, ductility, creep resistance of Mg alloys by adding rare earth (RE) elements, and it has been certified that the addition of RE do improve the performances of the Mg alloys. In this paper, we will review the progresses in the investigations of the Mg-RE alloys as a structural material, and also propose its application prospect in future.

scholarly journals Cyclic deformation behavior of rare-earth containing magnesium alloys

2021 ◽  
Author(s):  
Mirza Foisal Ahmed
Keyword(s):  
Rare Earth ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Weight Ratio ◽  
Mg Alloys ◽  
Mechanical Anisotropy ◽  
Cyclic Loading Condition ◽  
Secondary Cracks ◽  
Texture Modification ◽  
Re Elements

Lightweighting in ground vehicles is considered as one of the most effective strategies to improve fuel economy and reduce anthropogenic environment-damaging, climate-changing and costly emissions. Magnesium (Mg) alloy, as a strategic ultra-lightweight metallic material, has recently drawn a considerable interest in the transportation industry to reduce the weight of vehicles due to their high strength-to-weight ratio, dimensional stability, and good machinability and recyclability. However, the hexagonal close-packed crystal (HCP) structure of Mg alloys gives only limited slip systems and develops sharp crystallographic textures associated with strong mechanical anisotropy and tension-compression yield asymmetry. For the vehicle components subjected to dynamic loading, such asymmetry could exert an unfavorable influence on the material performance. These problems could be tackled through texture modification via addition of rare-earth (RE) elements. These RE-Mg alloys possess relatively weak initial textures, which lead to improved ductility and strength, and a reduction of the tension-compression asymmetry present in the conventional wrought Mg alloys. Despite the fact that the addition of RE elements sheds some light on the alterations in the mechanical anisotropy and the tension-compression yield asymmetry, the potential advantage of such RE-Mg alloys as structural components under cyclic loading condition has not been well appreciated. Thus, the main objective of this dissertation was to explore the cyclic deformation behavior of RE-Mg alloys under varying strain amplitudes and strain ratios, and correlate the behavior to the microstructural change and crystallographic texture weakening in the RE-Mg alloys in different states (extruded and heat-treated). Unlike the RE-free Mg alloys, these alloys exhibited essentially cyclic stabilization and fairly symmetrical hysteresis loops due to the weaker texture and reduced twinning-detwinning activities. While these alloys had a lower cyclic strain hardening exponent than the RE-free extruded Mg alloys, it had a longer fatigue life which can also be described by the Coffin-Manson law and Basquin’s equation. Fatigue crack was observed to initiate from the specimen surface with some cleavage-like facets near the initiation site. Crack propagation was basically characterized by fatigue striations in conjunction with secondary cracks. A detailed analysis for understanding the obstructive role of the precipitate to twinning has been also presented.

scholarly journals Alloying Elements of Magnesium Alloys: A Literature Review

2021 ◽  
Author(s):  
Nouha Loukil
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Magnesium Alloys ◽  
Clinical Applications ◽  
Mg Alloys ◽  
Alloying Elements ◽  
Strengthening Mechanisms ◽  
Corrosion Properties ◽  
Lightweight Structures ◽  
Re Elements

Magnesium alloys are the lightest structural metal. The lightness is the main reason for the interest for Mg in various industrial and clinical applications, in which lightweight structures are in high demand. Recent research and developments on magnesium Mg alloys are reviewed. A particular attention is focused on binary and ternary Mg alloys consisting mainly of Al, Zn, Mn, Ca and rare earth (RE) elements. The effects of different alloying elements on the microstructure, the mechanical and the corrosion properties of Mg alloys are described. Alloying induces modifications of the microstructural characteristics leading to strengthening mechanisms, improving then the ductility and the mechanical properties of pure Mg.

scholarly journals Cyclic deformation behavior of rare-earth containing magnesium alloys

2021 ◽  
Author(s):  
Mirza Foisal Ahmed
Keyword(s):  
Rare Earth ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Weight Ratio ◽  
Mg Alloys ◽  
Mechanical Anisotropy ◽  
Cyclic Loading Condition ◽  
Secondary Cracks ◽  
Texture Modification ◽  
Re Elements

Lightweighting in ground vehicles is considered as one of the most effective strategies to improve fuel economy and reduce anthropogenic environment-damaging, climate-changing and costly emissions. Magnesium (Mg) alloy, as a strategic ultra-lightweight metallic material, has recently drawn a considerable interest in the transportation industry to reduce the weight of vehicles due to their high strength-to-weight ratio, dimensional stability, and good machinability and recyclability. However, the hexagonal close-packed crystal (HCP) structure of Mg alloys gives only limited slip systems and develops sharp crystallographic textures associated with strong mechanical anisotropy and tension-compression yield asymmetry. For the vehicle components subjected to dynamic loading, such asymmetry could exert an unfavorable influence on the material performance. These problems could be tackled through texture modification via addition of rare-earth (RE) elements. These RE-Mg alloys possess relatively weak initial textures, which lead to improved ductility and strength, and a reduction of the tension-compression asymmetry present in the conventional wrought Mg alloys. Despite the fact that the addition of RE elements sheds some light on the alterations in the mechanical anisotropy and the tension-compression yield asymmetry, the potential advantage of such RE-Mg alloys as structural components under cyclic loading condition has not been well appreciated. Thus, the main objective of this dissertation was to explore the cyclic deformation behavior of RE-Mg alloys under varying strain amplitudes and strain ratios, and correlate the behavior to the microstructural change and crystallographic texture weakening in the RE-Mg alloys in different states (extruded and heat-treated). Unlike the RE-free Mg alloys, these alloys exhibited essentially cyclic stabilization and fairly symmetrical hysteresis loops due to the weaker texture and reduced twinning-detwinning activities. While these alloys had a lower cyclic strain hardening exponent than the RE-free extruded Mg alloys, it had a longer fatigue life which can also be described by the Coffin-Manson law and Basquin’s equation. Fatigue crack was observed to initiate from the specimen surface with some cleavage-like facets near the initiation site. Crack propagation was basically characterized by fatigue striations in conjunction with secondary cracks. A detailed analysis for understanding the obstructive role of the precipitate to twinning has been also presented.

Rare Earth Doped Zinc Oxide Nanowires

2008 ◽  
Vol 8 (1) ◽  
pp. 244-251 ◽  
Author(s):  
S. Geburt ◽  
D. Stichtenoth ◽  
S. Müller ◽  
W. Dewald ◽  
C. Ronning ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Rare Earth ◽  
Thermal Quenching ◽  
Wide Band ◽  
Wide Band Gap ◽  
Oxide Nanowires ◽  
Defect Sites ◽  
Optical Activation ◽  
Re Elements ◽  
Rare Earth Doped

Zinc oxide (ZnO) nanowires were grown via thermal transport and subsequently doped with different concentrations of Tm, Yb, and Eu using ion implantation and post annealing. High ion fluences lead to morphology changes due to sputtering; however, freestanding nanowires become less damaged compared to those attached to substrates. No other phases like rare earth (RE) oxides were detected, no amorphization occurs in any sample, and homogeneous doping with the desired concentrations was achieved. Photoluminescence measurements demonstrate the optical activation of trivalent RE-elements and the emission of the characteristic intra-4f-luminescence of the respective RE atoms, which could be assigned according to the Dieke-diagram. An increasing RE concentration results into decreasing luminescence intensity caused by energy transfer mechanisms to non-radiative remaining implantation defect sites. Furthermore, low thermal quenching was observed due to the considerable wide band gap of ZnO.

Modification in Texture of Magnesium by the Addition of Rare Earth Elements and its Influence on Mechanical Properties

2012 ◽  
Vol 736 ◽  
pp. 307-315 ◽  
Author(s):  
Murugavel Suresh ◽  
Satyam Suwas
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Magnesium Alloys ◽  
Aluminium Alloys ◽  
Room Temperature ◽  
Main Obstacle ◽  
Rare Earth Addition ◽  
Structural Applications ◽  
Re Elements ◽  
The Relationship

Mg alloys show limited room temperature formability compared to its lightweight counterpart aluminium alloys, which is a main obstacle in using this metal for most of the structural applications. However, it is known that grain refinement and texture control are the two possibilities for the improvement of formability of magnesium alloys. Amongst the approaches attempted for the texture weakening, additions through of rare-earth (RE) elements have been found most effective. The relationship between the texture and ductility is well established. In this paper, the effect of rare earth addition on texture weakening has been summarized for various magnesium alloys under the two most common modes of deformation methods.

scholarly journals Microstructure and Hardness of Scandium Trialuminide with Ternary Rare-Earth Additions

2007 ◽  
Vol 539-543 ◽  
pp. 1565-1570 ◽  
Author(s):  
Yoshihisa Harada ◽  
David C. Dunand
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
Lattice Parameter ◽  
Second Phase ◽  
Micro Hardness ◽  
Size Mismatch ◽  
Atomic Size ◽  
Rare Earth Additions ◽  
Re Elements ◽  
Vickers Micro Hardness

The microstructure of ternary Al3(Sc1-yREy) intermetallic compounds (where RE is one of the rare-earth elements La, Ce, Nd, Sm, Eu, Yb or Lu), was investigated as a function of RE concentration for 0<y≤0.75. Alloys with La, Ce, Nd, Sm or Eu additions consist of a L12 phase containing a dendritic second phase with D019 (La, Ce, Nd, Sm) or C11b (Eu) structure. Alloys with Yb or Lu additions show a single L12 phase. The RE solubility limits at 1373 K in the L12-Al3(Sc1-yREy) phase are very low for La, Nd, Ce and Eu (0.08-0.41 at.% or y=0.0032-0.0164), low for Sm (3.22 at.% or y=0.1288) and complete for Yb and Lu. The lattice parameter of the L12 solid-solution increases linearly with RE concentration and the magnitude of this effect is correlated with the atomic size mismatch between Sc and the RE elements. The Vickers micro-hardness of the L12 solid-solution increases linearly with increasing RE concentration.

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