Texture Change during Superplastic Deformation in Fine-Grained Magnesium Alloys

2016 ◽  
Vol 838-839 ◽  
pp. 59-65 ◽  
Author(s):  
Hiroyuki Watanabe ◽  
Tokuteru Uesugi ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Grain Boundary ◽  
Magnesium Alloys ◽  
Superplastic Deformation ◽  
Longitudinal Direction ◽  
Grain Boundary Sliding ◽  
Dislocation Slip ◽  
Grain Rotation ◽  
Fine Grained ◽  
Texture Change ◽  
Boundary Sliding

Texture change during superplastic deformation was examined and compared in two magnesium alloys with different chemical composition. These alloys were extruded to refine the microstructure. The pre-existing basal texture of both alloys became slightly more random within the bulk probably owing to grain boundary sliding and the accompanying grain rotation. However, the texture changes differed between tensile and compressive deformation along the extrusion (longitudinal) direction. This fact suggests that dislocation slip is important in superplastic deformation. It was concluded that dislocation slip acts primarily as an accommodation mechanism for grain boundary sliding.

scholarly journals Superplastic Tensile Deformation Behavior and Microstructural Evolution of Al–Zn–Mg–Cu Alloy

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 941
Author(s):  
Guangyu Li ◽  
Hua Ding ◽  
Jian Wang ◽  
Ning Zhang ◽  
Hongliang Hou
Keyword(s):  
Grain Boundary ◽  
Microstructural Evolution ◽  
Superplastic Deformation ◽  
Tensile Deformation ◽  
Grain Boundary Sliding ◽  
Recrystallization Process ◽  
Grain Rotation ◽  
Texture Intensity ◽  
Cu Alloy ◽  
Boundary Sliding

The microstructural evolution of the Al–Zn–Mg–Cu alloy during the superplastic deformation process has been studied by high temperature tensile experiment. The superplastic deformation behaviors are investigated under different temperatures of 470 °C, 485 °C, 500 °C, 515 °C and 530 °C, and different strain rates of 3 × 10−4 s−1, 1 × 10−3 s−1, 3 × 10−2 s−1 and 1 × 10−2 s−1. The microstructure observation shows that uniform and equiaxed grains can be obtained by dynamic recrystallization in the initial stage of superplastic deformation. Once the recrystallization process has been finished, the variations of the fraction of high angle boundary, the grain aspect ratio and the Schmid factor are negligible during the superplastic deformation, which shows that the grain boundary sliding and grain rotation are the main deformation mechanisms. The maximum texture intensity decreases compared with the initial microstructure, indicating that grain boundary sliding and grain rotation can weaken the texture, however, the texture intensity increases in the final stage of superplastic deformation, which may be resulted from the stress concentration.

Superplasticity in NiAl and NiAl-based alloys

2002 ◽  
Vol 17 (9) ◽  
pp. 2346-2356 ◽  
Author(s):  
J. J. Guo ◽  
X. X. Du ◽  
L. L. Zhou ◽  
B. D. Zhou ◽  
Y. Y. Qi ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Dynamic Recovery ◽  
Columnar Structure ◽  
Grain Boundary Sliding ◽  
Dislocation Slip ◽  
Directionally Solidified ◽  
Superplastic Behavior ◽  
Fine Grained ◽  
Fine Grained Structure ◽  
Boundary Sliding

Superplastic deformation was realized on NiAl and NiAl-based alloys prepared by both common casting and directional solidification. Directionally solidified NiAl–27Fe–3Nb alloy as well as conventionally cast NiAl, NiAl–25Cr, NiAl–9Mo, NiAl–20Fe–Y.Ce, and NiAl–30Fe–Y alloys exhibited typical deformation characteristics shown in conventionally superplastic materials. NiAl and NiAl-based alloys could be divided into three categories depending on their different superplastic behavior: finely grained structure (NiAl–9Mo, NiAl–25Cr, NiAl–20.4Fe–Y.Ce, NiAl–30Fe–Y), coarsely grained structure (NiAl), and columnar structure (NiAl–27Fe–3Nb). The corresponding deformation mechanisms for fine-grained structure, coarsely grained structure, and columnar structure were grain boundary sliding or grain boundary sliding accompanied by dynamic recrystallization, dynamic recovery and recrystallization, and intragrain dislocation slip, respectively.

scholarly journals Superplastic Deformation Mechanisms in Fine-Grained 2050 Al-Cu-Li Alloys

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2705
Author(s):  
Hongping Li ◽  
Xiaodong Liu ◽  
Quan Sun ◽  
Lingying Ye ◽  
Xinming Zhang
Keyword(s):  
Grain Boundary ◽  
Superplastic Deformation ◽  
Elevated Temperatures ◽  
Bulk Diffusion ◽  
Grain Boundary Sliding ◽  
Coordination Mechanism ◽  
Diffusion Creep ◽  
Fine Grained ◽  
Quantitative Calculation ◽  
Boundary Sliding

The deformation behavior and microstructural evolution of fine-grained 2050 alloys at elevated temperatures and slow strain rates were investigated. The results showed that significant dynamic anisotropic grain growth occurred at the primary stage of deformation. Insignificant dislocation activity, particle-free zones, and the complete progress of grain neighbor switching based on diffusion creep were observed during superplastic deformation. Quantitative calculation showed that diffusion creep was the dominant mechanism in the superplastic deformation process, and that grain boundary sliding was involved as a coordination mechanism. Surface studies indicated that the diffusional transport of materials was accomplished mostly through the grain boundary, and that the effect of the bulk diffusion was not significant.

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