Orientational Analysis on Static Recrystallization at Tension Twins in AZ31 Magnesium Alloy

2011 ◽  
Vol 299-300 ◽  
pp. 778-784
Author(s):  
Xiao Li ◽  
Ping Yang ◽  
Li Meng

The deformation depends on twinning in Mg alloy, and twins will be the dominant recrystallization nucleation site. Tension twinning proceeds much more easily than compression twinning since its volume fraction is much higher than that of compression twins, which may have a promotive effect on the recrystallization to a certain degree. Based on the previous research on the static recrystallization at compression twins, the evolution of microstructure and texture in AZ31 magnesium alloy during its static recystallization at tension twins was further investigated; and the orientational characteristics of new grains formed at tension twins in the early stage of static recrystallization were analyzed by EBSD technique. The results showed that the strong basal texture was retained and weakened with no new texture component being detected during annealing. New grains were observed to nucleate preferentially at the intersections of tension twin variants or the intersection between tension twins and compression twins. Their orientations are relatively random and are strongly scattered from those of original tension twins or compression twins. A comparison of the recrystallization at tension twins and compression twins was further made.

2005 ◽  
Vol 488-489 ◽  
pp. 633-636 ◽  
Author(s):  
Li Meng ◽  
Ping Yang ◽  
Zude Zhao ◽  
Wei Min Mao

Orientation mapping based on EBSD technique was applied to analyze the rules of orientation evolution of grains in AZ31 magnesium alloy. Results show that not only under deformation strain rate of 1×10-2s-1, but under 4×10-4s-1(the superplastic deformation condition), grains in all samples with initial textures rotate gradually to near basal orientation ({0002} || compression plane) at different ways, and basal texture becomes stronger with increasing strain, which indicates plastic slip plays an important role during hot deformation. Otherwise, no evident non-basal pyramidal slip of <a+c> as some studies mentioned was observed in the sample with the initial basal texture, and the basal orientation is kept unchanged during the deformation process, which suggests that basal slip is the uppermost plastic slip mechanism in this sample. In addition, the phenomenon of viscous laminar flow was observed in the sample with initial basal texture.


2012 ◽  
Vol 48 (8) ◽  
pp. 915 ◽  
Author(s):  
Hongtao HUANG ◽  
Andrew Godfrey ◽  
Wei LIU ◽  
Ruihe TANG ◽  
Qing LIU

Author(s):  
Qianren Tian ◽  
Guocheng Wang ◽  
Xinghu Yuan ◽  
Qi Wang ◽  
Seetharaman Sridhar

Nitride and carbide are the second phases which play an important role in the performance of bearing steel, and their precipitation behavior is complicated. In this study, TiN-MCx precipitations in GCr15 bearing steels were obtained by non-aqueous electrolysis, and their precipitation mechanisms were studied. TiN is the effective heterogeneous nucleation site for Fe7C3 and Fe3C, therefore, MCx can precipitate on the surface of TiN easily, its chemistry component consists of M3C and M7C3 (M = Fe, Cr, Mn) and Cr3C2. TiN-MCx with high TiN volume fraction, TiN forms in early stage of solidification, and MCx precipitates on TiN surface after TiN engulfed by the solidification advancing front. TiN-MCx with low TiN volume fraction, TiN and MCx form in late stage of solidification, TiN can not grow sufficiently and is covered by a large number of precipitated MCx particles.


2007 ◽  
Vol 539-543 ◽  
pp. 3359-3364 ◽  
Author(s):  
Tetsuo Sakai ◽  
Hiroshi Utsunomiya ◽  
H. Koh ◽  
S. Minamiguchi

Magnesium alloy sheets had to be rolled at elevated temperature to avoid cracking. The poor workability of magnesium alloy is ascribed to its hcp crystallography and insufficient activation of independent slip systems. Present authors have succeeded in 1-pass heavy rolling of AZ31 magnesium alloy sheet below 473K by raising rolling speed above 1000m/min. Heavy reduction larger than 60% can be applied by 1-pass high speed rolling even at room temperature. The improvement of workability at lower rolling temperature is due to temperature rise by plastic working. The texture of heavily rolled AZ31 magnesium alloy sheet is investigated in the present study. The texture of sheets rolled 60% at room temperature was <0001>//ND basal texture. At the rolling temperature above 373K, the peak of (0001) pole tilted ±10-15 deg toward RD direction around TD axisto form a double peak texture. The texture varied through thickness. At the surface, the (0001) peak tilted ±10-15 deg toward TD direction around RD axis to form a TD-split double peak texture. The direction of (0001) peak splitting rotated 90 deg from the surface to the center of thickness. Heavily rolled magnesium alloy sheets have non-basal texture. The sheets having non-basal texture are expected to show better ductility than sheets with basal texture.


2017 ◽  
Vol 20 (4) ◽  
pp. 1003-1009
Author(s):  
Lifei Wang ◽  
Miao Cao ◽  
Shuming Yang ◽  
Hua Zhang ◽  
Dongya Wang ◽  
...  

2012 ◽  
Vol 47 (11) ◽  
pp. 4561-4567 ◽  
Author(s):  
Xinsheng Huang ◽  
Kazutaka Suzuki ◽  
Yasumasa Chino ◽  
Mamoru Mabuchi

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 729 ◽  
Author(s):  
Yuanzhi Wu ◽  
Bin Deng ◽  
Tuo Ye ◽  
Zhicheng Nie ◽  
Xiao Liu

High strain rate multiple forging (HSRMF) was successfully carried out on AZ31 magnesium alloy at a temperature range of 250–400 °C, and the microstructure, texture and mechanical properties were examined. Full recrystallized structure developed at a relatively lower strain due to the twining induced dynamic recrystallization (TDRX) mechanism, which is also responsible for the feasibility of HSRMF deformation at relative low temperature. The average grain sizes of the alloys high strain rate multiple forged (HSRMFed) to the accumulated strain of ∑Δε = 1.32 increased from 7.07 to 9.99 μm as the temperature ranged from 250 to 400 °C, i.e., the grain sizes of the HSRMFed alloy were less sensitive to temperature. The weakened basal texture characteristic of titled or double peak achieved was ascribed to the alteration of forging direction. The HSRMFed alloys demonstrated both excellent strength (UTS > 300 MPa) and good ductility (δ > 20%), which resulted from the combined effects of grain refinement and weakened basal texture. Therefore, HSRMF was an efficient technique to produce strong and ductile wrought AZ31 alloy.


2016 ◽  
Vol 30 (01) ◽  
pp. 1550261 ◽  
Author(s):  
Feng Li ◽  
Nan Bian ◽  
Yongchao Xu ◽  
Xiang Zeng

In order to research the dynamic recrystallization (DRX) and grain refinement mechanisms in the process of extrusion through the rotating container, hot compression experiment of AZ31 magnesium alloy was carried out. Through the combination of experimental data and Yada empirical model, the DRX model of AZ31 magnesium alloy was established. Based on this DRX model, the numerical simulation of AZ31 magnesium alloy extrusion through the rotating container process was performed. The research results indicated, with the same process parameters of conventional extrusion, the shear stress increased significantly at the same position during the process of extrusion through the rotating container. This stress change promoted the occurrence of DRX and the increased recrystallization volume fraction. The average grain size obviously decreased. The equiaxed grains increased and the distribution uniformity was improved. These characteristics provided a theoretical basis for a better understanding of the enhanced comprehensive mechanical properties during the extrusion through the rotating container.


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