Forming Limit of AZ31 Magnesium Alloy Sheet under Non-Proportional Deformation at Elevated Temperature

2013 ◽  
Vol 535-536 ◽  
pp. 292-295 ◽  
Author(s):  
Takashi Katahira ◽  
Tetsuo Naka ◽  
Masahide Kohzu ◽  
Fusahito Yoshida

In the present work, FLDs of AZ31 magnesium alloy sheet for non-proportional strain paths were investigated by performing two-step stretch forming experiments at various forming speeds (3, 30 and 300 mm.min-1) at elevated temperatures of 150, 200 and 250°C. The forming limit strainSuperscript texts, both for proportional and non-proportional deformations, increased with temperature rise and with decreasing forming speed. A FLC after a uniaxial pre-strain lies outside of the proportional FLC for a given condition of temperature and forming speed, whereas a biaxially pre-strained FLC lies inside of the proportional FLC. It was found that the accumulated effective plastic strain and the direction of plastic strain increment at the final stage of forming are two major factors that influence the forming limits for non-proportional deformations.

2018 ◽  
Vol 941 ◽  
pp. 1270-1275
Author(s):  
Donato Sorgente ◽  
Gianfranco Palumbo ◽  
Alessandro Fortunato ◽  
Alessandro Ascari ◽  
Ali Arslan Kaya

The tailoring of mechanical and technological properties of the initial material in sheet metal forming has been widely investigated and successfully applied. The benefits of such an approach can be found in the improvement of both the post-forming performances of the manufactured component and the forming process capabilities. Different strategies can be found and most of them involve a microstructural alteration by a selective heat source (e.g. laser, induction, UV light). The use of aluminium alloys combined with these strategies has been extensively investigated, while magnesium alloys are almost not yet considered from this viewpoint. In this work, we investigated the effect of a selective laser heat treatment on an AZ31 magnesium alloy sheet. After laser heat treating a single track in the centre of a blank with different heat input values, bulge tests at elevated temperatures were conducted. The dome height evolution was continuously acquired during the tests and differences between the untreated specimen and the laser treated ones have been characterized. The effect of the laser treatment was evaluated also in terms of thickness distribution of the formed specimens. A thickness discontinuity was found along the treated specimens in the transition zone between the treated and the untreated material. Results highlighted that an effective change in the forming behaviour can be induced in the treated zone depending on the laser heat input. It has thus been shown that this approach can be employed for tailoring the magnesium alloy blank properties prior to the gas forming at elevated temperatures.


2010 ◽  
Vol 154-155 ◽  
pp. 1244-1250
Author(s):  
Peng Cheng Wang ◽  
Pei Wu ◽  
Zhi Yong Yue

In this paper, mechanical properties of unidirectional hot tensile tests of 3mm thick AZ31 magnesium alloy sheet metal are researched at elevated temperatures and under different tensile speeds. In this basis, thermal deep drawing of cylinders tests for 3mm thick AZ31 magnesium alloy sheet are investigated at elevated drawing temperatures, different drawing speeds and so on. Thermal deep drawing performance showed that set pieces better when elevated temperature and drawing speed range are appropriate to deep drawing.


2012 ◽  
Vol 509 ◽  
pp. 253-258 ◽  
Author(s):  
Fei Feng ◽  
Zheng Hua Meng ◽  
Shang Yu Huang ◽  
Jian Hua Hu ◽  
Zhi Lei He

Forming Limit Diagram of AZ31 magnesium alloy in different forming methods was researched in this paper. Experiment equipment and processes were improved successfully. Some tests and experiments (including tensile test, punch test and electromagnetic forming experiment) of AZ31 magnesium alloy sheet were done. Forming Limit Diagram of electromagnetic forming was established successfully. It could promote the application of magnesium alloy sheet in electromagnetic forming. Forming Limit Diagram of static forming was established successfully. It was very useful for the application of magnesium alloy sheet in other forming methods. The difference between these Forming Limit Diagram showed that electromagnetic forming obviously improve forming ability of the magnesium alloy sheet.


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.


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