Effects of Al and Zn on the Microstructure and Mechanical Properties of Magnesium Alloys

2010 ◽  
Vol 97-101 ◽  
pp. 801-804
Author(s):  
Jing Yuan Li ◽  
Xiao Lei Du

Two groups of magnesium alloys with various Al and Zn components are studied in this paper. One group of alloys are constant Al content of about 6% and various Zn content from 0 to 3%, another group are constant Zn content of about 0.4% and various Al content from 0 to 6%. The microstructures and mechanical properties of these alloys are investigated in as-cast and homogenized at 380°C for 15h. The results show that the tensile strength increases but yield strength decreases after homogenizing treatment. It can also be found that the morphology of second phrase and the size of grain exert the more effect on the mechanical properties than Zn content does. The alloys with uniform, fine and non-dendrite microstructure exhibit both high strength and elongation regardless of Zn content. On the other hand, the tensile strength and yield strength elevate significantly as Al content increases, and the elongation has a peak value in Al content of about 1.90%. The results show that the as-cast magnesium alloys with Al content of 5.6~6.0% and Zn content of 0.6~1.0% exhibit the best comprehensive mechanical properties.

2007 ◽  
Vol 546-549 ◽  
pp. 391-394
Author(s):  
Ding Fei Zhang ◽  
Li Ping Ren ◽  
Hong Ju Zhang ◽  
Wei Yuang

Developing new alloys and techniques is important for the applications of magnesium alloy products. The greatest challenge in the area is to exploit new wrought magnesium alloys[1]. In this paper, the effects of Zn addition on the microstructures and mechanical properties of the MZK60 wrought alloy which is modified from ZK60 have been investigated. The microstructures of these alloys at various states were evaluated by optical microscopy. The mechanical properties at room temperature of these alloys were studied systematically by tensile test. Experimental results indicated that increasing Zn content to 7~10%wt is able to get not only higher tensile strength and yield strength, but also higher elongation.


2011 ◽  
Vol 686 ◽  
pp. 113-119
Author(s):  
Jing Yuan Li ◽  
Xiao Lei Du

The mechanical property of magnesium alloy depends on the alloy elements and microstructure strongly. The multiple dependency relations are studied by investigating magnesium alloys with different Al and Zn contents. The semi-continuous casting billets exhibit quite different microstructural morphologies between the centre and edge of the cross section. The centre shows fine and uniform microstructure while the edge is coarse and reticular. However the difference is almost eliminated when the billets were homogenized at 380°C for 15h. The generation mechanism of casting microstructure is also discussed in this paper. The results show that the morphology of second phase and the size of grain have greater effect on the mechanical properties than the element Zn. The alloys with uniform, fine and non-dendrite microstructure exhibit both high strength and elongation when Al content is about 6% and Zn content is various from 0 to 3%. In contrast, the strength increases and elongation decreases significantly as Al content increases from 0 to 6%.


2009 ◽  
Vol 610-613 ◽  
pp. 826-830
Author(s):  
Tian Mo Liu ◽  
Wei Hui Hu ◽  
Qing Liu

The microstructures and mechanical properties of cold upsetting magnesium alloys were investigated upon anneal under different conditions. The results show that a large amount of twins were observed in the original grains of cold upsetting AZ31 magnesium alloys. The twins disappeared gradually and recrystal grains formed after anneal. The volume fraction of the recrystal grains increases as the strain of samples rises. Recrystal grain size grows large with the elevated annealing temperature. Recrystal grain size reduces at first and then grows as the annealing time is prolonged. In addition, compared with as-cast magnesium alloys, the yield strength of cold upsetting samples increase apparently due to grain refinement after anneals.


2016 ◽  
Vol 61 (2) ◽  
pp. 475-480
Author(s):  
K. Bolanowski

Abstract The paper analyzes the influence of different heat treatment processes on the mechanical properties of low-alloy high-strength steel denoted by Polish Standard (PN) as 10MnVNb6. One of the findings is that, after aging, the mechanical properties of rolled steel are high: the yield strength may reach > 600 MPa, and the ultimate tensile strength is > 700 MPa. These properties are largely dependent on the grain size and dispersion of the strengthening phase in the ferrite matrix. Aging applied after hot rolling contributes to a considerable rise in the yield strength and ultimate tensile strength. The process of normalization causes a decrease in the average grain size and coalescence (reduction of dispersion) of the strengthening phase. When 10MnVNb6 steel was aged after normalization, there was not a complete recovery in its strength properties.


2012 ◽  
Vol 545 ◽  
pp. 247-250 ◽  
Author(s):  
Subramanian Jayalakshmi ◽  
Khoo Chee Guan ◽  
Kuma Joshua ◽  
Manoj Gupta

Magnesium alloys are the lightest structural materials known that are increasingly replacing steel and aluminium. However, due to its flammable nature, protective atmospheres are employed during Mg-alloy production. In this novel work, Mg-Al alloys with ~3 and ~5 wt.% Al were processed in CO2atmosphere, so as to utilize the CO2during the melting process. The cast Mg-Al alloys were extruded and studied for their structural, physical and mechanical properties. Results showed improvements in mechanical properties such as hardness, tensile strength and compressive yield strength. The improvement in properties was attributed to thein situformation of Al4C3arising due to molten metal-carbon interaction. It is noteworthy that the incorporation of CO2during processing did not adversely affect the mechanical properties of the alloys. Further, the process is eco-friendly as it not only utilized CO2, but also eliminates use of harmful cover gases.


This paper reviews the outcome of bismuth and antimony trappings on the microstructure and mechanical behavior of an assortment of commercial magnesium alloys. Various compositions of the Bi and Sb were discussed along with/without combination of other alloying elements. These additions have revealed to be resulted in the formation of Mg3Bi2 , Mg3Sb2 intermediate phases when added upon with corresponding alloying elements. Moreover the reasons for the observed changes due to the addition of these alloying elements were also reviewed. It is found that the accumulation of Bi phase as well as intermetallics and Sb intermediates has greatly improved the microstructure belonging to the as cast magnesium alloys thereby improving both mechanical and thermo-mechanical properties. It is also observed in the review that addition of thesealloying elements acted as grain refiner and improved the corrosion resistance of commercial magnesium alloys.


2021 ◽  
Vol 63 (4) ◽  
pp. 303-310
Author(s):  
Feipeng Zhu ◽  
Xiaoxia Gu ◽  
Pengxiang Bai ◽  
Dong Lei

Abstract High-strength steel plays an important role in engineering fields such as infrastructure. For this reason, an accurate determination of its mechanical properties is of critical importance. Considering the inconvenience of conventional mechanical extensometers for the deformation measurement of small-scale specimens, 3D digital image correlation (3D-DIC) was used to measure the deformation of Grade 8.8 bolts and Q690 high-strength steel specimens by means of a uniaxial tensile test, and in this way, stress–strain curves, elastic modulus, yield strength, tensile strength, percentage elongation after fracture, and percentage reduction of area were obtained. Experimental results show that Grade 8.8 bolts and Q690 steel result in higher yield strength and tensile strength than common steel. Moreover, owing to the phenomenon that stress remains constant with strain increase in the yielding stage, the evolution process from elastic deformation to plastic deformation of the specimens during the yielding stage could be studied. Experimental results show that the axial strain of Grade 8.8 bolts increases from 0.3 to 1 % during the yielding stage and for Q690 specimens the corresponding strain increases from 0.4 to 1.8 %.


2013 ◽  
Vol 747-748 ◽  
pp. 443-448
Author(s):  
Feng Wang ◽  
Ji Bao Li ◽  
Ping Li Mao ◽  
Zheng Liu

A high strength and toughness extruded Mg-Zn-Y alloy based on quasicrystal-strengthening has been studied. The effect of extrusion and heat treatment on the microstructures and mechanical properties of Mg-Zn-Y alloy were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrum (EDS), X-ray diffraction (XRD) and tensile testing. The experimental results indicated that the coarse dendrite crystals were broken through the hot extrusion, and dynamic recrystallization appeared during the hot extrusion, which obviously refined the hot-extruded microstructure to the average grain size about 20μm. A large amount of strengthening phases such as Mg3Zn6Y(I-Phase), Mg12ZnY(X-Phase) and MgZn2, which were massive, grainy and clavate, dispersedly precipitated from the matrix along grain boundary during ageing treatment at 225 after extrusion, and made the sliding of grain boundaries restrained, which resulted in an enhancement for mechanical properties to a great extent. At the same time, the tensile strength and yield strength increased after ageing treatment. After ageing treatment of 225×24h, the highest tensile strength and yield strength of the extruded Mg-Zn-Y alloy were obtained: σb=506.7MPa, σ0.2=373.5MPa, which were increased by 104.8% and 120.4%, respectively, compared with the extruded Mg-Zn-Y alloy, however the elongation decreased to 16.52%.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5219
Author(s):  
Milan Šmak ◽  
Jaroslav Kubíček ◽  
Jiří Kala ◽  
Kamil Podaný ◽  
Jan Vaněrek

Modern high-strength steels achieve their strength exclusively through the manufacturing process, as the chemical composition of these steels is very similar to the composition of standard-quality steels. Typically, hot-dip galvanizing is used to form a protective zinc layer on the steel parts of structures; nonetheless, the material is exposed to high temperatures during the process. With high-strength steels, this can lead to deterioration of the mechanical properties. This study aims to experimentally examine and evaluate the extent of deterioration of the mechanical properties of high-strength-steel members. The effect was studied on specimens made of three different types of steel with the yield strength ranging from 460 to 1250 MPa. For each type of steel, selected mechanical properties—yield strength, tensile strength, and hardness—were determined on specimens with and without hot-dip galvanization, and the obtained results were mutually compared. Our study shows a significant impact of the hot-dip galvanization process on the mechanical properties of some high-strength steels. With the studied types of steel, the yield strength decreased by up to 18%, the tensile strength by up to 13%, and the hardness by up to 55%.


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