scholarly journals Study on the Strengthening Mechanism of Rare Earth Ce in Magnesium Alloys, Based on First-Principle Calculations and Electronegativity Theory

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6681
Author(s):  
Yanfei Chen ◽  
Zhengqiang Zhu ◽  
Jixue Zhou ◽  
Huasheng Lai
Keyword(s):  
Rare Earth ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Energy Dispersive Spectrometer ◽  
Alloy System ◽  
Strengthening Mechanism ◽  
First Principle ◽  
First Principle Calculations ◽  
Second Phases ◽  
Re Elements

Since the commercial applications of rare earth magnesium alloys are increasing gradually, there are considerable advantages to developing lower cost and higher performance magnesium alloys with high abundance rare earth (RE) elements. However, the alloying order of a matrix magnesium alloy is completely changed with the addition of RE elements. Therefore, further study of the strengthening mechanism of Ce element in magnesium alloys is required. In this work, the thermodynamic stability of the possible second phases in a Mg-Al-Mn-Ce multicomponent magnesium alloy were analyzed, based on first-principle calculations, and the precipitation sequence of the key RE phases was deduced as a consequence. Combined with Scanning Electron Microscope (SEM), X-ray Diffractometer (XRD), Energy Dispersive Spectrometer (EDS), and other experimental methods, it was investigated whether the preferentially precipitated second phases were the nucleation core of primary α-Mg. The complex alloying problem and strengthening mechanism in a multi-elemental magnesium alloy system were simplified with the aid of electronegativity theory. The results showed that the preferentially precipitated Al11Ce3 and Al10Ce2Mn7 phases could not be the nucleation core of primary α-Mg, and the grain refinement mechanism was such that the second phases at the grain boundary prevented the growth of magnesium grains. Moreover, the tensile test results showed that the reinforced structure, in which the Al-Ce phase was mixed with Mg-Al phase, was beneficial for improving the mechanical properties of magnesium alloys, at both ambient temperature and high temperature.

Development of the Microstructure and Texture of RE Containing Magnesium Alloys during Hot Rolling

2010 ◽  
Vol 654-656 ◽  
pp. 580-585 ◽  
Author(s):  
Karl Ulrich Kainer ◽  
Joachim Wendt ◽  
Kerstin Hantzsche ◽  
Jan Bohlen ◽  
Sang Bong Yi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Rare Earth ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Hot Rolling ◽  
Transverse Direction ◽  
Threshold Concentration ◽  
Wrought Magnesium Alloy ◽  
Re Elements

Commercial magnesium alloys such as AZ31 exhibit strong crystallographic textures during massive deformation such as rolling. A randomisation of the texture, however, was found in alloys with rare earth (RE) elements in solid solution. This paper describes the development of microstructure and texture during rolling of the Al-free RE-containing wrought magnesium alloy ZEK100 during hot rolling. This alloy develops a strong texture with a pronounced component towards the transverse direction (TD) of the sheets. This TD component forms already after the first rolling pass, persists through all following passes and is further enhanced by subsequent heat treatment. These results are contrasted with results from a study on texture development of binary RE containing Mg-alloys, which show that the presence of RE elements alone is not responsible for the tilt of basal planes towards the TD. There is, however, a threshold concentration at which the texture begins to weaken.

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.

Development of New Types of Magnesium Alloys Containing Sr or RE Elements

2007 ◽  
Vol 561-565 ◽  
pp. 191-197 ◽  
Author(s):  
Fu Sheng Pan ◽  
Ming Bo Yang ◽  
Yan Long Ma
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnesium Alloys ◽  
Research Results ◽  
Microstructure And Properties ◽  
Minor Addition ◽  
Re Elements

The latest research results on new types of magnesium alloys containing strontium or rare earth elements are reviewed. Special attentions are paid to the alloying design, microstructure and properties controlling, the influence of minor addition of Sr and RE on the microstructure and properties of existing magnesium alloys. Some new types of magnesium alloys containing Sr or RE are introduced and discussed.

Effect of LaCl3 on the Structure and Properties of Magnesium Alloys

2005 ◽  
Vol 488-489 ◽  
pp. 111-114 ◽  
Author(s):  
Guo Hua Wu ◽  
Hong Tao Guo ◽  
Xiao Qing Zeng ◽  
Wen Jiang Ding
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Testing Machine ◽  
Mg Alloy ◽  
Image Analyzer ◽  
Universal Material Testing Machine ◽  
Alloy Properties ◽  
Re Elements ◽  
Mg Melt

By use of the Zwick electronic universal material testing machine, X-ray diffractometer, SEM, EDX, image analyzer and corrosion test, the effects of LaCl3 on the mechanical properties, structure, fractography and corrosion behavior of magnesium alloy have been studied. The results show that minute nodular Al10La2Mn7 phases can be formed in Mg melts after fluxes containing LaCl3 are added to Mg melt. The Al10La2Mn7 phases can act as the nucleating site of γ phases, and the γ phases can be refined. With the flux containing 5% LaCl3, the σb and δ of the Mg alloy can be improved from 161MPa and 2.1% to 203MPa and 4.0% by 26% and 100%, respectively. The corrosion rate of magnesium alloys can decrease from 1.10 mg/(cm2.d) to 0.17 mg/(cm2.d) by 84% with the use of flux containing 5% LaCl3. Rare earth (RE) elements are often added to the magnesium alloy to improve the alloy structure and the room or elevated temperature mechanical properties. But up to present, the RE elements added to Mg melt is often in the form of pure RE alloy or RE master alloy [1]. Because RE is the oxidizable material, this kind of adding process often leads to low RE utilization ratio and high use-cost. Besides, this process can easily induce segregation of RE and the appeared coarse RE phases will lower the Mg alloy mechanical properties. By far, there is few research reports about RE contained compound added to Mg alloy melt. In this paper, the effects of Lanthanum chloride (LaCl3) on the structure and mechanical properties of Mg alloy are studied for the first time. The aim is to explore a new way to improve the Mg alloy properties.

First Principles Calculations for Alloy Design of Moderate Temperature Age-Hardenable Al Alloys

2006 ◽  
Vol 519-521 ◽  
pp. 35-44 ◽  
Author(s):  
Ai Wu Zhu ◽  
Gary J. Shiflet ◽  
E.A. Jr. Starke
Keyword(s):  
Design Criterion ◽  
Alloy Design ◽  
Strengthening Effect ◽  
First Principle ◽  
Alloy Development ◽  
Fundamental Properties ◽  
First Principle Calculations ◽  
Structural Applications ◽  
Second Phases ◽  
Cluster Variation

For aerospace structural applications of age-hardenable aluminum at temperatures above 100°C, a primary alloy-design criterion is creep resistance which depends on the strengthening effect and thermal stability of the second phases.. First principle calculations can be used to study fundamental properties of these phases and, therefore, help to identify the desired ones and their precipitate structures. In order to produce the desired phases, which are usually thermodynamically metastable, and to suppress the undesired phases, computational analysis (combining first principle calculations, cluster variation methods and CALPHAD) can assist in identifying beneficial trace additions and deleterious impurities that must be eliminated. This paper, using Al-Cu-Mg as an example, illustrates this approach, which if successful, should shorten the normal alloy development period.

Effects of Heat Treatments on Microstructure of AM50 Magnesium Alloy

2007 ◽  
Vol 26-28 ◽  
pp. 103-106
Author(s):  
Yan Long Ma ◽  
Fu Sheng Pan ◽  
Ming Bo Yang
Keyword(s):  
Solid Solution ◽  
Magnesium Alloy ◽  
Strengthening Mechanism ◽  
Heat Treatments ◽  
Aged Sample ◽  
Testing Conditions ◽  
Solution Treated ◽  
Treated Sample ◽  
Second Phases ◽  
Am50 Alloy

The effects of different solid solution and aging technologies on the microstructure of AM50 were studied. The results indicated that heat-resistant Al-Mn phases were the major second phases in AM50 alloy under all testing conditions. Highest microhardnesses were obtained not only in as-aged sample but in as-solution treated sample, which indicated that the strengthening mechanism for AM50 alloy was not limited to precipitation reinforcement.

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