scholarly journals Superplasticity at Intermediate Temperatures of ZK60 Magnesium Alloy Processed by Indirect Extrusion

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 606
Author(s):  
César Palacios-Trujillo ◽  
José Victoria-Hernández ◽  
David Hernández-Silva ◽  
Dietmar Letzig ◽  
Marco A. García-Bernal
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Deformation Mechanism ◽  
Extrusion Direction ◽  
Grain Boundary Sliding ◽  
Mg Alloys ◽  
Homogeneous Microstructure ◽  
Texture Measurement ◽  
Average Grain Size ◽  
Zk60 Magnesium Alloy

Magnesium alloys usually exhibit excellent superplasticity at high temperature. However, many Mg alloys have poor formation ability near room temperature. Therefore, preparation of Mg alloys with suitable microstructures to show low or intermediate temperature superplasticity is an important goal. In this work, the superplastic behavior at intermediate temperatures of a commercial ZK60 magnesium alloy processed by indirect extrusion was investigated. After extrusion, the alloy showed a refined and homogeneous microstructure with an average grain size of 4 ± 2 μm. Overall texture measurement indicated that the alloy showed a strong prismatic texture with the highest intensity oriented to pole ⟨101¯0⟩. A texture component ⟨1¯21¯1⟩ parallel to the extrusion direction was found; this type of texture is commonly observed in Mg alloys with rare earth additions. Tensile tests were performed at temperatures of 150, 200, and 250 °C at three strain rates of 10−2, 10−3, and 10−4 s−1. A very high ductility was found at 250 °C and 10−4 s−1, resulting in an elongation to failure of 464%. Based on calculations of the activation energy and on interpretation of the deformation mechanism map for magnesium alloys, it was concluded that grain boundary sliding (GBS) is the dominant deformation mechanism.

Effect of Deformation Ratios on Microstructure and Mechanical Properties of ZK60 Magnesium Alloy by Hydrostatic Extruded at Room Temperature

2012 ◽  
Vol 557-559 ◽  
pp. 13-17
Author(s):  
Rong Wang ◽  
Xiu Rong Zhu ◽  
Gang Chen ◽  
Jing Jiang Nie ◽  
Yong Dong Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Deformation Mechanism ◽  
Room Temperature ◽  
Elongation Rate ◽  
Microstructure And Mechanical Properties ◽  
Deformation Ratio ◽  
Zk60 Magnesium Alloy

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.

Effect of Heat Treatment on Tensile Strength and Microstructure of AZ61A Magnesium Alloy

2014 ◽  
Vol 606 ◽  
pp. 55-59 ◽  
Author(s):  
R. Senthil ◽  
A. Gnanavelbabu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Mg Alloys ◽  
Forming Process ◽  
Microstructural Parameters ◽  
Heat Treated ◽  
Mutual Relations

Magnesium alloys are the very progressive materials whereon is due to improve their end-use properties. Especially, wrought Mg alloys attract attention since they have more advantageous mechanical properties than cast Mg alloys. Investigations were carried out the effects of heat treatment on tensile strength and microstructure of AZ61A magnesium alloy. The AZ61A Mg alloy is solution heat treated at the temperature of 6500F (343°C) for various soaking timing such as 120 min, 240 min and 360 minutes and allowed it cool slowly in the furnace itself. Magnesium alloys usually are heat treated either to improve mechanical properties or as means of conditioning for specific fabrication operations. Special attention had been focused on the analysis of mutual relations existing between the deformation conditions, microstructural parameters, grain size and the achieved mechanical properties. The result after the solution heat treatment, showed remarkably improved hardness, tensile strength and yield strength. It would be appropriate for a forming process namely isostatic forming process.

Anomalous Twinning as the Macroscopic Deformation Mechanism for AZ31 Magnesium Alloy

2019 ◽  
Vol 810 ◽  
pp. 95-100
Author(s):  
Yusuke Onuki ◽  
Shigeo Sato
Keyword(s):  
Magnesium Alloy ◽  
Deformation Mechanism ◽  
Tensile Deformation ◽  
Tensile Axis ◽  
Rolling Direction ◽  
Az31 Magnesium Alloy ◽  
Uniaxial Tensile ◽  
Rolled Sheet ◽  
Prism Slip ◽  
Texture Measurement

In order to study the plastic deformation mechanism of AZ31 magnesium alloy, in situ texture measurement during uniaxial tensile deformation is conducted by using neutron diffraction. The specimen is prepared from a rolled sheet so that the deformation axis is parallel to the rolling direction. By increasing strain, the alignment of <10-10> along the tensile axis is strengthened, which is due to the activation of the prism slip system. The basal pole concentration at the prior sheet normal direction is slightly decreased by the deformation and the new texture component is formed at the transvers direction. This can be understood by activation of the {10-12} tension twinning. These results indicate that the tension twinning plays an important role even when the tensile deformation is applied parallel to the basal plane.

Microstructure Evolution in Magnesium Alloy ZK60 during Cyclic Extrusion and Compression

2014 ◽  
Vol 1035 ◽  
pp. 259-262
Author(s):  
Fei Han ◽  
Hong Wei Liu ◽  
Gang Chen
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Microstructural Evolution ◽  
Microstructure Evolution ◽  
Extrusion Ratio ◽  
Technical Parameters ◽  
Average Grain Size ◽  
Zk60 Magnesium Alloy ◽  
Refinement Effect

The microstructural evolution of of as-cast ZK60 magnesium alloy processed by cyclic extrusion and compression (CEC) were studied, and the effects of technical parameters on microstructural evolution were investigated. The results show that the grains of as-cast ZK60 magnesium alloy were obviously refined and uniformed by CEC, the average grain size was decreased from original 50 ~ 60 μm to about 2 μm when the extrusion ratio was 8 with 8-passes at 350°C, and the refinement effect was increased with the rising of extrusion ratio and passes. The effect of increasing passes on grain refinement was not obvious when it exceeds 8. Nevertheless, it is beneficial for the grain homogenization.

Dislocation Plasticity and Complementary Deformation Mechanisms in Polycrystalline Mg Alloys

2004 ◽  
Vol 449-452 ◽  
pp. 665-668 ◽  
Author(s):  
Junichi Koike
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Deformation Mechanism ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Mg Alloys ◽  
Deformation Mechanisms ◽  
Slip Systems ◽  
Dislocation Plasticity ◽  
Boundary Sliding

Deformation mechanisms of Mg-Al-Zn (AZ31) alloys were investigated by performing tensile test at room temperature. In fine grain Mg alloys deformed at room temperature, nonbasal slip systems were found to be active as well as basal slip systems because of grain-boundary compatibility effect. Slip-induced grain-boundary sliding occurred as a complementary deformation mechanism to give rise to c-axis component of strain. With increasing grain size, the activation of the nonbasal slip systems was limited near grain boundaries. Instead of grain-boundary sliding, twinning occurred as a complementary deformation mechanism in large grained samples. Orientation analysis of twins indicated that twinning is induced by stress concentration due to the pile up of basal dislocations. The grain-size dependence on deformation mechanism was found to affect yielding behavior both microscopically and macroscopically which can influence various mechanical properties such as fatigue and creep.

MagForge – Mechanical Behaviour of Forged AZ31B Extruded Magnesium in Monotonic Compression

2015 ◽  
Vol 828-829 ◽  
pp. 291-297 ◽  
Author(s):  
Andrew Gryguc ◽  
Hamid Jahed ◽  
Bruce Williams ◽  
Jonathan McKinley
Keyword(s):  
Tensile Strength ◽  
Magnesium Alloy ◽  
Ultimate Tensile Strength ◽  
Mechanical Behaviour ◽  
Deformation Mechanism ◽  
Extrusion Direction ◽  
Strain Behaviour ◽  
Dominant Deformation Mechanism ◽  
Slip Deformation ◽  
Material Conditions

Monotonic compression testing was conducted on AZ31B-F magnesium alloy in both the as-received and forged conditions. Sigmoidal stress strain behaviour was the key feature in the majority of material conditions and directions corresponding to plastic behaviour where twinning de-twinning is the dominant deformation mechanism. More conventional monotonic hardening (slip deformation mechanism) was exhibited in certain material directions which initially were orthogonal to the extrusion direction in the as-received condition, but once forged are coincident with the direction of forging once forged. It was shown that in the forged condition, there is potential for significant increases in both ultimate tensile strength as well as strain to failure.

Tensile Properties and Microstructure of ZK60 Magnesium Alloys at High Temperature

2011 ◽  
Vol 117-119 ◽  
pp. 1113-1116
Author(s):  
Wen Jie Cheng ◽  
Fu Xiao Chen
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Flow Behavior ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Maximum Elongation ◽  
Superplastic Behavior ◽  
Boundary Sliding ◽  
Zk60 Magnesium Alloy ◽  
Main Deformation

Using tensile test of ZK60 magnesium alloy, the superplastic flow behavior was studied. The deformation temperature was set as 280°C, 310°C,340°C, 370°C and 400°C while strain rate was 1×10-1s-1, 1×10-2s-1, 1×10-3s-1 and 1×10-4s-1. The results showed that the perfect superplastic behavior was presented at 370°C and =1×10-4s-1 and the maximum elongation could be 133.7%. The biggest factor of strain rate sensitivity was 0.62. The microstructure of the fracture was analyzed used SEM and the results showed that the main deformation mechanism of ZK60 magnesium alloy was grain boundary sliding.

scholarly journals The Effect of Friction Stir Processing (FSP) on the Microstructure and Properties of AM60 Magnesium Alloy

2016 ◽  
Vol 61 (3) ◽  
pp. 1555-1560 ◽  
Author(s):  
J. Iwaszko ◽  
K. Kudła ◽  
K. Fila ◽  
M. Strzelecka
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Friction Stir Processing ◽  
Structural Changes ◽  
Flow Line ◽  
Homogeneous Microstructure ◽  
X Ray ◽  
Friction Stir ◽  
Average Grain Size

Abstract The samples of the as-cast AM60 magnesium alloy were subjected to Friction Stir Processing (FSP). The effect of FSP on the microstructure of AM60 magnesium alloy was analyzed using optical microscopy and X-ray analysis. Besides, the investigation of selected properties, i.e. hardness and resistance to abrasion wear, were carried out. The carried out investigations showed that FSP leads to more homogeneous microstructure and significant grain refinement. The average grain size in the stirred zone (SZ) was about 6-9 μm. in the thermomechanically affected zone (TMAZ), the elongated and deformed grains distributed along flow line were observed. The structural changes caused by FSP lead to an increase in microhardness and wear resistance of AM60 alloy in comparison to their non-treated equivalents. Preliminary results show that friction stir processing is a promising and an effective grain refinement technique.

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