Microstructure, texture, and mechanical properties of friction stir spot welded rare-earth containing ZEK100 magnesium alloy sheets

2014 ◽  
Vol 618 ◽  
pp. 637-644 ◽  
Author(s):  
R.I. Rodriguez ◽  
J.B. Jordon ◽  
H.M. Rao ◽  
H. Badarinarayan ◽  
Wei Yuan ◽  
...  
2016 ◽  
Vol 850 ◽  
pp. 784-789
Author(s):  
Song Lin Chen ◽  
Da Tong Zhang

AZ31 magnesium alloy was friction stir spot welded in air and cooling in water. The effect of the enhanced cooling rate on the microstructure and mechanical properties of the joint was analyzed. The results showed that flowing water had obvious cooling effect instantaneously, which significantly restrained the growth of dynamic recrystallized grains. The average grain size in stir zone was 1.3μm in cooling water condition, which is far smaller than that of the joint prepared in air cooling condition. Under the condition of enhanced cooling, the microhardness in stir zone significantly increased, the ultimate tensile load (~ 3.99kN) increased by 15.7%, and the tensile deformation value (~ 3.65 mm) increased by 62.2%. Dimples in SEM fracture morphologies indicated the better plastic deformation capacity of joints prepared by cooling water, which failed through a mixture mode of ductile and brittle fracture.


Author(s):  
N Sivashanmugam ◽  
KL Harikrishna ◽  
S R Koteswara Rao ◽  
N Rameshbabu ◽  
P Manojkumar

Abstract Magnesium and its alloys are extensively used in the defence, aerospace and automotive industries, owing to their excellent mechanical properties. But there is a requirement of corrosion prevention treatment before using it for applications, since the corrosion resistance of Mg alloy is poor. In this work, a study on the mechanical properties of friction stir welded ZE41 rare earth magnesium alloy thick plates of 15mm and 25mm, was carried out. A metallographic examination and mechanical tests were conducted on both the welds. Furthermore, Plasma Electrolytic Oxidation (PEO), a surface conversion treatment was carried out on both the base material as well as on the friction stir butt joints. X-ray diffraction and scanning electron microscopy analysis were carried out on all the samples, with and without coating. The coated and uncoated samples were assessed by potentiodynamic polarisation (PDP) tests and electrochemical impedance spectroscopy (EIS) to study the electrochemical corrosion behaviour. An outer porous layer and an inner dense layer, have been identified from the SEM images. From the corrosion tests results it was revealed that there was an improvement in the corrosion resistance of both the base metal as well as the weldments by the PEO coating process.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Huijie Liu ◽  
Yunqiang Zhao ◽  
Xingye Su ◽  
Lilong Yu ◽  
Juncai Hou

2A12-T4 aluminum alloy was friction stir spot welded, and the microstructural characteristics and mechanical properties of the joints were investigated. A softened microstructural region existed in the joint, and it consisted of stir zone (SZ), thermal mechanically affected zone (TMAZ), and heat affected zone (HAZ). The minimum hardness was located in TMAZ, and the average hardness value in SZ can be improved by appropriately increasing welding heat input. The area of complete bonding region at the interface increased with increasing welding heat input because more interface metals were mixed. In a certain range of FSSW parameters, the tensile shear failure load of the joint increased with increasing rotation speed, but it decreased with increasing plunge rate or decreasing shoulder plunging depth. Two kinds of failure modes, that is, shear fracture mode and tensile-shear mixed fracture mode, can be observed in the tensile shear tests, and the joint that failed in the tensile-shear mixed fracture mode possessed a high carrying capability.


2007 ◽  
Vol 546-549 ◽  
pp. 563-566
Author(s):  
Wen Jiang Ding ◽  
Guo Hua Wu ◽  
Bong Sun You ◽  
Dong Yim Chang

The effects of CeCl3-containing fluxes on RE element loss, the high temperature mechanical properties, microstructure and corrosion properties of magnesium alloy containing RE have been studied. The results showed that a certain amount of CeCl3 in purification fluxes restrained the reaction between the Ce element and fluxes to decrease the loss of Ce in alloys. With the flux containing 9% CeCl3, the loss rate of alloy element Ce can be reduced from 26.9% to 3.4%, and the σb and δ of the alloys at 150°C counld be improved from 160.9MPa and 6.2% to 176.5MPa and 7.9% compared with that of conventional MgCl2-containing flux , respectively. Besides, the coarse β phase and rod-like RE phase were refined effectively by CeCl3-containing fluxes.


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