Effect of Pass Thickness Reduction on Microstructure and Formability in AZ31 Magnesium Produced by Differential Speed Rolling

2012 ◽  
Vol 152-154 ◽  
pp. 18-23
Author(s):  
Wei Jun Xia ◽  
Ling Liu ◽  
Fu Quan Zhang ◽  
Cong Chang Xu
Keyword(s):  
Thickness Reduction ◽  
Speed Ratio ◽  
Strain Hardening Exponent ◽  
Anisotropy Ratio ◽  
Basal Texture ◽  
Deformation Bands ◽  
Normal Anisotropy ◽  
Low Pass ◽  
Differential Speed Rolling ◽  
Differential Speed

AZ31 magnesium alloy sheets were prepared by multi-pass differential speed rolling (DSR) with small mismatch roll speed ratio. Effect of pass thickness reduction on microstructure, texture and formability at room temperature were investigated. The results showed that the low pass thickness reduction DSR is effective to improve the formability by refining the grain size and weakening the basal texture, which is characterized by the increasing of strain hardening exponent (n value) and elongation as soon as decreasing of yielding ratio and normal anisotropy ratio (r value). With the increasing of pass thickness reduction, more effective grain refinement is achieved due to the forming of deformation bands. While the ability of forming the title basal texture is weakened and the formability is reduced.

scholarly journals Microstructure, Texture and Mechanical Properties of Mg-6Sn Alloy Processed by Differential Speed Rolling

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 83
Author(s):  
Kamil Majchrowicz ◽  
Paweł Jóźwik ◽  
Witold Chromiński ◽  
Bogusława Adamczyk-Cieślak ◽  
Zbigniew Pakieła
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Rolling Direction ◽  
Speed Ratio ◽  
Basal Texture ◽  
Electron Backscattered Diffraction ◽  
Normal Anisotropy ◽  
Average Grain Size ◽  
Differential Speed Rolling ◽  
Differential Speed

The effect of shear deformation introduced by differential speed rolling (DSR) on the microstructure, texture and mechanical properties of Mg-6Sn alloy was investigated. Mg-6Sn sheets were obtained by DSR at speed ratio between upper and lower rolls of R = 1, 1.25, 2 and 3 (R = 1 refers to symmetric rolling). The microstructural and textural changes were investigated by electron backscattered diffraction (EBSD) and XRD, while the mechanical performance was evaluated based on tensile tests and calculated Lankford parameters. DSR resulted in the pronounced grain refinement of Mg-6Sn sheets and spreading of basal texture as compared to conventionally rolled one. The average grain size and basal texture intensity gradually decreased with increasing speed ratio. The basal poles splitting to transverse direction (TD) or rolling direction (RD) was observed for all Mg-6Sn sheets. For the as-rolled sheets, YS and UTS increased with increasing speed ratio, but a significant anisotropy of strength and ductility between RD and TD has been observed. After annealing at 300 °C, Mg-6Sn sheets became more homogeneous, and the elongation to failure was increased with higher speed ratios. Moreover, the annealed Mg-6Sn sheets were characterized by a very low normal anisotropy (0.91–1.16), which is normally not achieved for the most common Mg-Al-Zn alloys.

Mechanical properties of Mg–Al–Zn alloy with a tilted basal texture obtained by differential speed rolling

2008 ◽  
Vol 488 (1-2) ◽  
pp. 214-220 ◽  
Author(s):  
Xinsheng Huang ◽  
Kazutaka Suzuki ◽  
Akira Watazu ◽  
Ichinori Shigematsu ◽  
Naobumi Saito
Keyword(s):  
Mechanical Properties ◽  
Basal Texture ◽  
Differential Speed Rolling ◽  
Zn Alloy ◽  
Differential Speed

Influences of Rolling Conditions on Texture and Mechanical Properties of AZ31 Magnesium Alloy Processed by Differential Speed Rolling

2007 ◽  
Vol 561-565 ◽  
pp. 287-290
Author(s):  
Kazutaka Suzuki ◽  
Xin Sheng Huang ◽  
Akira Watazu ◽  
Ichinori Shigematsu ◽  
Naobumi Saito
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Rolling Direction ◽  
Rolling Temperature ◽  
Az31 Magnesium Alloy ◽  
Speed Ratio ◽  
Shear Direction ◽  
Differential Speed Rolling ◽  
Press Formability ◽  
Differential Speed

It was reported that the cold and warm press formability of the magnesium alloy was improved by the application of a differential speed rolling (DSR). However, it can be considered that the microstructure and the texture of the DSR processed sheets greatly change with the rolling conditions. In this study, commercial AZ31B magnesium alloy extrusions were processed by DSR at a differential speed ratio of 1.167 and a reduction per pass of 10% or less, and the effects of the rolling temperature, the number of rolling passes and reversal of the rolling direction on texture and mechanical properties were examined. As a result, it was found that the optimal rolling temperature in terms of the workability and formability of the material was 573 K. And the elongation and formability were maximal in sheets processed by 4–6 passes of DSR. Moreover, reversing the shear direction made the microstructure more homogeneous and finer than unidirectional shear, and improved the mechanical properties and formability. This improvement was greater in samples where the shear direction was reversed once in the middle than where it was reversed for each pass.

scholarly journals Effect of Grain Refinement and Dispersion of Particles and Reinforcements on Mechanical Properties of Metals and Metal Matrix Composites through High-Ratio Differential Speed Rolling

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4159 ◽  
Author(s):  
Ahmad Bahmani ◽  
Woo-Jin Kim
Keyword(s):  
Mechanical Properties ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
High Speed ◽  
Large Scale ◽  
High Ratio ◽  
Speed Ratio ◽  
Matrix Composites ◽  
Differential Speed Rolling ◽  
Differential Speed

A differential speed rolling (DSR) technique that provides capability of producing large-scale materials with fine grains and controlled texture in a continuous manner has attracted several researchers and industries. In this study, we tried to review the articles related to DSR and especially the high-ratio DSR (HRDSR) technique that is associated with a high speed ratio between the upper and lower rolls (≥2) and compare the change in microstructure and mechanical properties after HRDSR with the results obtained by using other severe plastic deformation (SPD) techniques to see the potential of the HRDSR technique in enhancing the mechanical properties of metals and metal matrix composites. The reviewed results show that HRDSR is an important technique that can effectively refine the grains to micro or nano sizes and uniformly disperse the particles or reinforcement throughout the matrix, which helps extensively in improving ambient and superplastic mechanical properties of various metals and alloys.

Microstructure and Texture Control of Al-Mg Alloy Sheets by Differential Speed Rolling

2005 ◽  
Vol 495-497 ◽  
pp. 597-602 ◽  
Author(s):  
Tetsuo Sakai ◽  
K. Yoneda ◽  
S. Osugi
Keyword(s):  
Shear Strain ◽  
Shear Deformation ◽  
Rolling Direction ◽  
Deformation Texture ◽  
Speed Ratio ◽  
Roll Speed ◽  
Shear Texture ◽  
Differential Speed Rolling ◽  
R Value ◽  
Differential Speed

Large shear deformation was successfully introduced in 5182 aluminum alloy sheets by 2-pass differential speed warm rolling under a high friction condition. The roll speed ratio was varied from 1.0 to 2.0. When the roll speed ratio was smaller than 1.4, shear strain increased near the surface, but the strain decreased to zero at the mid-thickness. At a roll speed ratio larger than 1.4, shear strain was introduced even at the mid-thickness, and it increased near the surface. Thus the shear strain increased with the roll speed ratio. After 2-pass differential speed rolling, a large shear strain prevailed throughout the thickness. The rolling direction of the second pass was so selected that the direction of shear deformation introduced in the second pass was similar to (unidirectional shear rolling) or opposite (reverse shear rolling) that in the first pass. A shear texture with main components of {111}<110>, {112}<110> and {001}<110> prevailed throughout the thickness, and conventional rolling textures such as {112}<111> or {123}<634> orientation were not detected in any part of thickness. The rolling direction of the second pass had little effect on the deformation texture. After recrystallization annealing, the shear texture components were retained. The intensity of the shear texture components after recrystallization was almost similar to the deformation texture. The r-value of the annealed sheet was slightly increased and the planar anisotropy of the r-value was decreased by differential speed rolling. Differential speed rolling, by which shear deformation can be introduced throughout the thickness, was thus shown to be a promising process for improving the physical and mechanical properties of rolled and annealed aluminum alloy sheets by texture control.

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