Effect of RE on Microstructure and Properties of AM60 Magnesium Alloy

2014 ◽  
Vol 1004-1005 ◽  
pp. 172-176
Author(s):  
Yao Li ◽  
Jun Jie Yang ◽  
Ping Xue ◽  
Zhi Jiang Zuo

Industrial AM60 magnesium alloy, to which mixed rare earth containing Y, Gd and Nd elements is added, was used to study the effects of rare earth (RE) on their casting microstructures and properties. The experimental results showed that RE could effectively improve grain refinement and the internal organization, which transferred the Mg17Al12 phase from the network structure into grainy one. The microscopic analysis indicated that by adding the mixed RE, the amount of Mg17Al12 compounds was less than that without mixed RE on the grain boundaries, and it was replaced by Al-RE compounds. In addition, the mechanical properties of the alloy with mixed RE had been significantly improved and the maximum tensile strength was up to about 260MPa and the elongation rate could reach more than 10%. When the mixed RE content was more than 2%, coarse Al-RE compounds were formed in the alloy, which degraded the mechanical properties.

2011 ◽  
Vol 291-294 ◽  
pp. 1082-1086
Author(s):  
Yao Jin Wu ◽  
Zhi Ming Zhang ◽  
Bao Cheng Li ◽  
Bao Hong Zhang ◽  
Jian Min Yu ◽  
...  

In the present research, the influences of different extrusion ratios (15, 30, 45, 60, and 75) and extrusion temperature (300°C, 330°C, 360°C, 390°C, 420°C) on the mechanical properties and microstructure changes of AZ80 magnesium alloy have been investigated through tensile test and via ZEISS digital metallographic microscope observation. Research indicates that the alloy’s plasticity gradually decreases as the temperature increases, and that the alloy’s tensile strength varies with the extrusion ratio. At 330°C, the alloy’s particle grain is small and a small amount of black hard and brittle second-phase β (Mg17Al12) are precipitated uniformly along the grain boundary causing the gradual increase of the alloy’s tensile strength. When the extrusion temperature is up to 390°C, the grain size increases significantly, but the second phase precipitation along grain boundaries transforms into continuous and uniform-distribution precipitation within the grain. In this case, when the extrusion ratio is 60, the alloy’s tensile strength reaches its peak 390 Mpa. As the extrusion temperature increases, inhomogeneous precipitation of the second-phase along grain boundaries increases, causing the decrease of the alloy’s strength. At the same temperature, both the tensile strength and plasticity increases firstly and then decreases as extrusion ratio increases. With the gradual increase of the refinement grain, the dispersed precipitates increase and the alloy’s tensile strength and plasticity reach their peaks when the extrusion temperature is 390°C. As the grain grows, the second phase becomes inhomogeneous distribution, and the alloy’s strength and plasticity gradually decrease.


2012 ◽  
Vol 479-481 ◽  
pp. 27-30
Author(s):  
Ju Mei Zhang ◽  
Zhi Hu Wang ◽  
Wan Chang Sun ◽  
Li Bin Niu

The atomic diffusion and mechanical properties of as-cast AZ80 magnesium alloy after solution treatment at different time were studied by OM,SEM,EDS as well as tensile testing. The results show that the coarse β-Mg17Al12 phase distributed along the grain boundaries as net microstructure is almost dissolved after solution treatment, and the content of Al that in the α-Mg matrix is well distributed with the solution time prolonged. Because of the β-Mg17Al12 phase reducing and granulating, the function of precipitates phase strengthening was depressed and the hardness (HB) of alloy dropped obviously. However, the tensile strength(σb ) and elongation(δ) enhanced remarkably and the yield strength (σ0.2) decreased slightly.


Author(s):  
R. Ahmad Et.al

The influence of samarium (Sm) content on the solidification characteristics, microstructure, and mechanical properties of Mg–2.8wt%Nd–1.5wt%Gd–0.5wt%Zn–0.5wt%Zr magnesium alloy was studied. The cooling curves and microstructure analysis results showed that Sm rare earth element refined the grains of the alloys, where the solidification time of α-Mg phase of decreased as addition of Sm, which reflected to the microstructure of alloy and the grains became refined, also Sm combined with the initial phase of the intermetallic base alloy and crystallized along the grain boundaries. In addition, Mg41Sm5, Mg3Zn6Sm and (Mg, Zn)3Sm new intermetallic phases were formed as addition of Sm. Both grain refinement and formed intermetallic phases led to the improvement in hardness and tensile strength.


2014 ◽  
Vol 960-961 ◽  
pp. 87-91
Author(s):  
Zhi Chao Liu ◽  
Yao Li ◽  
Jun Jie Yang

Rare earth Y、Gd、Nd were added to improve the tensile strength, elongation, hardness and microstructure of AZ91D magnesium alloy in this study. The investigation had been undertaken by 8 GWU type resistance furnace, RGM - 50 electronic machine , Vickers ,etc. Results show that a moderate amount of composite adding rare earth can effectively improve the tensile strength of AZ91D alloy, elongation, hardness and the organizational structure, as a rare earth content increased after the first performance decline. When rare earth content is 1.8%, the highest tensile strength up to 276.58mpa, 8.3% elongation. When rare earth content is 2.4%, the hardness is up to 99.36 HV1.96.


2010 ◽  
Vol 146-147 ◽  
pp. 267-271
Author(s):  
Chang Qing Li ◽  
Quan An Li ◽  
Xing Yuan Zhang ◽  
Qing Zhang

The microstructure and mechanical properties of aged Mg-5.5Al-0.5Y magnesium alloy with Sm addition were investigated. The results show that with proper content of Sm addition, the microstructure of Mg-5.5Al-0.5Y magnesium alloy is refined obviously. The quantity of β-Mg17Al12 phase is reduced, and Al2Sm particle phase is formed. With the increase of Sm addition, the mechanical properties of the alloy at room and elevated temperature increase at first, and then decrease. When the content of Sm is up to 1%, the values of tensile strength and elongation at room temperature,150 and 175 are up to their maxima synchronously, 244MPa/20.07%, 217MPa/18.86% and 185MPa/19.15% respectively.


2020 ◽  
Vol 39 (1) ◽  
pp. 200-208
Author(s):  
Tao Lin ◽  
Ji-Xue Zhou ◽  
Cai-Nian Jing ◽  
Yun-Teng Liu ◽  
Lin-Lin Zhang ◽  
...  

AbstractFew studies of cryogenic treatment were focused on nonferrous alloys, such as magnesium alloy. In this work, the effect of cryogenic treatment (77 K) before extrusion on microstructure and mechanical properties of ZK60 alloy was investigated. The results showed that many fine G.P. zones were formed during the cryogenic treatment and then grew to short fine {\beta }_{1}^{^{\prime} } precipitates when heating before extrusion. These precipitates pinned dynamic recrystallized grain boundaries in the subsequent extrusion, resulting in fine gains and dispersed spherical precipitates. By the cryogenic treatment before extrusion, the extruded ZK60 alloy showed good tensile strength and elongation balance. Especially, elongation was improved by 29%.


2011 ◽  
Vol 686 ◽  
pp. 253-259
Author(s):  
Xu Ning ◽  
Wei Dong Xie ◽  
Chun Mei Dang ◽  
Xiao Dong Peng ◽  
Yan Yang ◽  
...  

A series of Mg-6Al-2Sr-1.5Y-xNd (x=0, 0.3, 0.6, 0.9, 1.2) alloy samples were prepared and their microstructures were observed and mechanical properties were measured. The existing forms of Y and Nd were studied. The effects of Y and Nd on microstructure and mechanical properties of AJ62 alloy were investigated. The results show that the main existing forms of Y and Nd in AJ62 alloy are Al2Y and Al2Nd. The combined addition of rare earth Y and Nd can refine α-Mg matrix obviously and reduce the amount of the β-Mg17Al12phases; after solid solution treatment, the tensile strength of the alloys rise first and fall later with increasing content of Nd. When the content of Nd is about 0.6%wt, the values of tensile strengthes are up to the maximum both at room temperature and at 448 K.


2005 ◽  
Vol 475-479 ◽  
pp. 2449-2452
Author(s):  
Nam Young Suk ◽  
Kyung Sub Lee

The effects of Ca addition on the microstructure and mechanical properties of AZ91 magnesium alloy have been investigated. The main changes in microstructure caused by Ca addition were the grain refinement in the as-cast alloys and the formation of new Al2Ca phase along the grain boundaries. The tensile strength and elongation of the AZ91 magnesium alloy were improved by small addition of Ca due to grain refinement and replacement of Mg17Al12 phase with new Al2Ca compound. However, when above 0.7wt.% Ca was added, mechanical properties of AZ91 magnesium alloy were decreased.


2012 ◽  
Vol 557-559 ◽  
pp. 13-17
Author(s):  
Rong Wang ◽  
Xiu Rong Zhu ◽  
Gang Chen ◽  
Jing Jiang Nie ◽  
Yong Dong Xu ◽  
...  

The effect of different hydrostatic extrusion ratios on the microstructure and mechanical properties of the ZK60 magnesium alloys were investigated. The results showed that, the major deformation mechanism of the alloy is twinning at room temperature, which resulted in that the tensile strengthen and hardness of the extruded alloy improved greatly. With deformation ratio increasing, the ultimate tensile strengthen and hardness are linearly increased, with the functions of Y= 4.2X+358.3 and Y=2.3X +73.69, respectively. And the maximum tensile strength and hardness of the extruded alloy are 383 MPa and 87HB, respectively. But the elongation decreases obviously, the minimum decreasing degree is 50%. With the deformation ratio increasing, the tendency of elongation rate increased as an “M” model.


Author(s):  
Wenxue Fan ◽  
Hai Hao

Abstract Grain refinement has a significant influence on the improvement of mechanical properties of magnesium alloys. In this study, a series of Al–Ti–C-xGd (x = 0, 1, 2, 3) master alloys as grain refiners were prepared by self-propagating high-temperature synthesis. The synthesis mechanism of the Al–Ti–C-xGd master alloy was analyzed. The effects of Al–Ti–C-xGd master alloys on the grain refinement and mechanical properties of AZ31 (Mg-3Al-1Zn-0.4Mn) magnesium alloys were investigated. The results show that the microstructure of the Al–Ti–C-xGd alloy contains α-Al, TiAl3, TiC and the core–shell structure TiAl3/Ti2Al20Gd. The refining effect of the prepared Al–Ti–C–Gd master alloy is obviously better than that of Al–Ti–C master alloy. The grain size of AZ31 magnesium alloy was reduced from 323 μm to 72 μm when adding 1 wt.% Al–Ti–C-2Gd master alloy. In the same condition, the ultimate tensile strength and elongation of as-cast alloy were increased from 130 MPa, 7.9% to 207 MPa, 16.6% respectively.


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