Superplasticity in Friction Stir Processed AZ80 Magnesium Alloy

2010 ◽  
Vol 433 ◽  
pp. 241-246 ◽  
Author(s):  
Yoshimasa Takayama ◽  
Itsuki Takeda ◽  
Toshiya Shibayanagi ◽  
Hajime Kato ◽  
Kunio Funami
Keyword(s):  
Magnesium Alloy ◽  
Cross Section ◽  
Room Temperature ◽  
Maximum Stress ◽  
Strain Rates ◽  
Friction Stir ◽  
Az80 Magnesium Alloy ◽  
Lower Strain ◽  
Elongation To Failure ◽  
Scanning Electron

Superplasticity in an AZ80 magnesium alloy subjected to friction stir processing (FSP) has been investigated. FSP was carried out at two traveling speeds of 150mm/min and 300mm/min for grain refinement. Optical microscopy on cross section to processing direction revealed obvious differences in size and feature between the stir zones at the two traveling speeds. The hardness of FSPed sample at the room temperature was about 30HV higher than that of as-received one. The maximum stress of the FSPed sample was reduced remarkably at lower strain rates compared with those of the as-received one at 573K and 673K. On the other hand, the elongation to failure of the FSPed sample showed ten to thirteen times larger than that of the as-received one at 573K and low strain rates. Further surface morphology near the fracture tip was observed by scanning electron microscopy to discuss deformation mechanism at high temperatures.

Influence of Annealing Treatment on Precipitation of β-Mg17Al12 Phase of AZ80 Magnesium Alloy

2012 ◽  
Vol 476-478 ◽  
pp. 55-58 ◽  
Author(s):  
Ju Mei Zhang ◽  
Zhi Hu Wang ◽  
Bai Ling Jiang ◽  
Zi Shan Chen ◽  
Li Bin Niu
Keyword(s):  
Magnesium Alloy ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Longitudinal Direction ◽  
Lamellar Spacing ◽  
Element Distribution ◽  
Isothermal Process ◽  
Β Phase ◽  
Az80 Magnesium Alloy ◽  
The Matrix

The microstructure and element distribution of AZ80 magnesium alloy as-cast and after annealing treatment were studied by OM, SEM, XRD, EDS and TEM. The results show that the coarse divorced eutectic phase distributed along the grain boundary dissolve into Mg matrix during the isothermal process at 415°C for 24h. During the cooling process of annealing treatment, the lameller-shape β-Mg17Al12 nucleated preferentially in the grain near the boundary, then grows towards the neighbor grains with longitudinal direction, which precipitated from magnesium solid solution as perlite-type precipitation. When cooled to room temperature, the lameller-shape β-Mg17Al12 was uniformly distributed in the matrix, and the lamellar spacing inside β phase is about 1-2μm.

Enhanced Tensile Ductility of AZ80 Magnesium Alloy

2011 ◽  
Vol 284-286 ◽  
pp. 1635-1638
Author(s):  
Jun Qiao ◽  
Yu Wang ◽  
Guo Dong Shi ◽  
Bao Xin Nie
Keyword(s):  
Tensile Tests ◽  
Grain Boundary Sliding ◽  
Dislocation Creep ◽  
Strain Rates ◽  
Premature Failure ◽  
Az80 Magnesium Alloy ◽  
Coarse Grains ◽  
Elongation To Failure ◽  
Boundary Sliding ◽  
Cavity Evolution

Tensile behaviors of extruded and rolled AZ80 Mg alloy were investigated with elongation-to-failure tensile tests at constant temperatures of 300 °C, 350 °C, 400 °C, and 450 °C, and constant strain rates of 10-2s-1and 10-3s-1. Experimental data show that the material exhibits tensile ductilities of over 100% at 400 °C and 450 °C, featured by long steady state deformation. Microstructure studies show that annealed coarse grains were remained in the gauge region during the tensile tests, and the enhanced tensile ductilities resulted from dislocation creep, other than dynamic recrystallization or grain boundary sliding. Cavity evolution and recrystallized coarse grains near fracture end caused premature failure of the material.

Mechanical Properties and Microstructure of AZ31 Magnesium Alloy under Uni-Axial Tensile Loading

2011 ◽  
Vol 686 ◽  
pp. 219-224 ◽  
Author(s):  
Xiao Yu Zhong ◽  
Guang Jie Huang ◽  
Fang Fang He ◽  
Qing Liu
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Alloy Sheet ◽  
Strain Rates ◽  
Axial Tensile ◽  
Magnesium Alloy Az31b ◽  
Plastic Deformation Behavior ◽  
Electron Back Scattered Diffraction

Uni-axial tensile plastic deformation behavior of rolled magnesium alloy AZ31B under the temperature range from room temperature(RT) to 250°C with strain rates between 10-3 and 10-1s-1 has been systematically investigated. Microstructure evolution and texture were determined using optical microscopy (OM) and electron back-scattered diffraction (EBSD) techniques, respectively. Our results indicated that the strength and elongation-to-fracture were more sensitive to strain rates at elevated temperature rather than that at room temperature; dynamic recrystallization (DRX) and relaxation of stress at elevated temperature resulted in dramatic change of mechanical properties. Compared with strain rate, the temperature played a more important role in ductility of AZ31B Mg alloy sheet.

Grain Refinement and High Temperature Deformation in Friction Stir Processed Sheets of Magnesium Alloys

2007 ◽  
Vol 551-552 ◽  
pp. 55-60 ◽  
Author(s):  
Yoshimasa Takayama ◽  
Y. Otsuka ◽  
Toshiya Shibayanagi ◽  
Hajime Kato ◽  
Kunio Funami
Keyword(s):  
High Temperature ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Maximum Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Rolled Sheet ◽  
Friction Stir ◽  
Fine Grain ◽  
Elongation To Failure

Grain refinement and high temperature deformation in two kinds of magnesium alloys subjected to friction stir processing (FSP) have been investigated. One was a rolled sheet of LA141Mg and another was a cast plate of AZ91Mg. FSP was developed by adapting the concepts of friction stir welding to obtain a fine grain size in a stirred zone. Grain refinement was achieved by FSP to give fine grain sizes of 11.4μm and 8.4μm for LA141 and AZ91 alloys, respectively. For LA141 alloy, the maximum stress of the FSPed sample was higher than that of the as-received one in the range of 300K to 523K while the elongation to failure of the former was considerably smaller than that of the latter. On the other hand, the elongation for the FSPed sample of AZ91Mg showed three times larger elongation with a lower maximum stress than the as-received cast one at 523K and 2.8×10-3s-1. Further difference in high temperature deformation for both magnesium alloys was discussed based on microstructural change and stress-strain curves.

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