Microstructure and Mechanical Properties of Extruded Mg-Zn-Y Alloy

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%.

2017 ◽  
Vol 898 ◽  
pp. 97-103 ◽  
Author(s):  
Zheng Hua Huang ◽  
Nan Zhou ◽  
Jing Xu ◽  
Yang De Li ◽  
Wei Rong Li

The microstructures, phase constitutions and mechanical properties of as-cast samples, extruded rods and plates of Mg-3.52Sn-3.32Al and Mg-6.54Sn-4.78Al alloys were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction and mechanical testing. The results show that as-cast microstructure consists of α-Mg matrix, Mg2Sn and a few dispersed β-Mg17Al12 phases. The two as-cast alloys exhibit good tensile mechanical properties. After hot extrusion, dynamic recrystallization occurs. Average grain size reaches 6 μm ~ 8 μm for rods, and a lot of fine micro-scaled particles exist, resulting in significant enhancement of tensile mechanical properties. The extruded Mg-3.52Sn-3.32Al rod exhibits better comprehensive tensile mechanical property than AZ31B alloy, with tensile strength σb of 295 MPa, yield strength of 200 MPa and elongation of 21.5% at ambient temperature. The extruded Mg-6.54Sn-4.78Al rod exhibits equivalent comprehensive tensile mechanical properties with ZK60 alloy, achieving tensile strength of 355 MPa, yield strength of 275 MPa and elongation of 11% at ambient temperature. The extruded plates at ambient temperature performed a tensile strength of 270 MPa.


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.


2018 ◽  
Vol 37 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Hansong Xue ◽  
Xinyu Li ◽  
Weina Zhang ◽  
Zhihui Xing ◽  
Jinsong Rao ◽  
...  

AbstractThe effects of Bi on the microstructure and mechanical properties of AZ80-2Sn alloy were investigated. The results show that the addition of Bi within the as-cast AZ80-2Sn alloy promotes the formation of Mg3Bi2 phase, which can refine the grains and make the eutectic phases discontinuous. The addition of 0.5 % Bi within the as-extruded AZ80-2Sn alloy, the average grain size decreases to 12 μm and the fine granular Mg17Al12 and Mg3Bi2 phases are dispersed in the α-Mg matrix. With an increase in Bi content, the Mg17Al12 and Mg3Bi2 phases become coarsened and the grain size increases. The as-extruded AZ80-2Sn-0.5 %Bi alloy has the optimal properties, and the ultimate tensile strength, yield strength and elongation are 379.6 MPa, 247.1 MPa and 14.8 %, respectively.


2011 ◽  
Vol 682 ◽  
pp. 49-54
Author(s):  
Bin Chen ◽  
Chen Lu ◽  
Dong Liang Lin ◽  
Xiao Qin Zeng

The Mg96Y3Zn1 alloy processed by equal channel angular pressing has been investigated. It was found that the Mg96Y3Zn1 alloy processed by ECAP obtained ultrafine grains and exhibits excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy refined to about 400 nm. The highest strengths with yield strength of 381.45MPa and ultimate tensile strength of 438.33MPa were obtained after 2 passes at 623K. It was found that cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test. As a result, the elongation of alloy is decreased with pass number increasing.


2016 ◽  
Vol 861 ◽  
pp. 147-152
Author(s):  
Fei Yang ◽  
Brian Gabbitas ◽  
Ajit Singh ◽  
Chung Fu Wang

In this paper, pure titanium rods, with high strength and ductility, were prepared by vacuum sintering titanium powder compacts at 1300oC for 2h and then hot extruding the as-sintered titanium billets at 900oC in air. The microstructure and property changes, after vacuum sintering and hot extrusion, were investigated. The results showed clear evidence of porosity in the microstructure of as-sintered titanium billet and tensile testing of as-sintered material gave yield strength, ultimate tensile strength and ductility values of 570MPa, 602MPa and 4%, respectively. After extrusion at 900oC, no obvious pores could be seen in the microstructure of as-extruded titanium rod, and the mechanical properties were significantly improved. The yield strength, ultimate tensile strength and the ductility reached 650MPa, 705MPa and 20%, respectively, which are much higher than values for CP titanium (grade 4), with a yield strength of 480MPa, ultimate tensile strength of 550MPa and ductility of 15%. The fracture characteristics of as-sintered and as-extruded titanium rods have also been investigated.


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 %.


2011 ◽  
Vol 284-286 ◽  
pp. 1101-1105
Author(s):  
Hong Mei Zhang ◽  
Li Feng Qiao

The effect of reduction on the microstructure refinement and mechanical properties of the as-hot rolled dual-phase Nb-bearing steel were studied at laboratory. It is found that the dual-phase steel displays clearly classic dual phase morphology which is ferrite and martensite or bainsite, and the fine island or lath martinsite is dispersed on the matrix of ferrite by the observation of microstructure. The grain can be refined, and the increased precipitated second particles are fined and dispersed with the increasing of reduction. The mechanical properties determination result shows that the mechanical properties have greatly improved by large reduction. The tensile strength obtained in the laboratory is up to 680MPa, the ratio of yield strength and tensile strength is low, and the elongation is better.


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%.


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.


2012 ◽  
Vol 05 ◽  
pp. 342-349
Author(s):  
M. S. MOHEBBI ◽  
A. AKBARZADEH

A novel SPD process for manufacturing high strength tubes and cylinders titled as accumulative spin-bonding (ASB) is proposed. This process is applied to a commercially pure aluminum up to four cycles and its effects on the microstructure and mechanical properties are examined by optical microscopy, TEM, microhardness and tension tests. The results show that ultra-fine grains are developed during the process leading to a nanostructure with average grain size in order of 150 nm. Mechanical properties indicate that while the hardness of outer layers is more than inner ones, the hardness and its homogeneity is increased by increasing the ASB cycles. As a result of grain refinement and the scheme of hardness development, the yield and tensile strength of material are increased significantly up to the values of 194 and 235 MPa, respectively.


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