Effect of Lubrications on Quick Plastic Forming Behavior of AZ31 Magnesium Alloy Sheet

2013 ◽  
Vol 690-693 ◽  
pp. 2222-2225
Author(s):  
Gang Wang ◽  
Jian Long Wang ◽  
Zhi Peng Zhang ◽  
Shen Jie Yao
Keyword(s):  
Magnesium Alloy ◽  
Thickness Distribution ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy Sheet ◽  
Part Surface ◽  
Plastic Forming ◽  
Quick Plastic Forming ◽  
Formed Part ◽  
Microscopic Morphology ◽  
Lubrication Conditions

Lubrication plays important role in Quick Plastic Forming (QPF). Friction coefficient between AZ31B magnesium alloy and the die steel was examined by ring upsetting tests at 400°C with no lubrication, boron nitride (BN), graphite and molybdenum disulfide respectively. The effect of the four lubrication conditions on bulging height and wall thickness distribution of conical, rectangular and cylinder components in QPF within 300s was investigated. Macroscopic and microscopic morphology of the formed part surface in the four conditions was observed.

Quick Plastic Forming Behavior of AZ91 Magnesium Alloy Sheet

2011 ◽  
Vol 314-316 ◽  
pp. 842-846
Author(s):  
Gang Wang ◽  
Zhi Peng Zhang ◽  
Cheng Bo Liu ◽  
Xia Sheng
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Alloy Sheet ◽  
Gas Pressure ◽  
Test Results ◽  
Free Gas ◽  
Magnesium Alloy Sheet ◽  
Plastic Forming ◽  
Quick Plastic Forming ◽  
Bulging Test

The quick plastic forming (QPF) behavior for fine-grained AZ91D magnesium alloy sheet with the thickness of 1.0 mm and the grain size of 6.0 µm was investigated. Free gas bulging tests were conducted under different gas pressure for 300 s in the range of 250-400°C to investigate how the temperature and pressure impact on the formability of QPF. Free gas bulging test results show that the bulge height of semisphere part exist the peak value of 33 mm under the gas pressure of 0.5 MPa at 400°C. QPF tests of cup part were performed based on the free gas bulging test results. A cup part with the height of 20 mm which both of surface quality and fillet radius were satisfactory was formed using a two-stage loading path at 400°C during 300 s. Furthermore the microstructural revolution law during the QPF was discussed. The larger the thinning rate of parts is, the smaller the grain size will be.

Texture of AZ31 Magnesium Alloy Sheet Heavily Rolled by High Speed Warm Rolling

2007 ◽  
Vol 539-543 ◽  
pp. 3359-3364 ◽  
Author(s):  
Tetsuo Sakai ◽  
Hiroshi Utsunomiya ◽  
H. Koh ◽  
S. Minamiguchi
Keyword(s):  
Magnesium Alloy ◽  
High Speed ◽  
Room Temperature ◽  
Alloy Sheet ◽  
Rolling Temperature ◽  
Az31 Magnesium Alloy ◽  
Basal Texture ◽  
Double Peak ◽  
Magnesium Alloy Sheet ◽  
Az31 Magnesium Alloy Sheet

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.

Enhanced Formability of AZ31 Magnesium Alloy Sheet Processed by Equal Channel Angular Rolling and Annealing Treatment

2007 ◽  
Vol 26-28 ◽  
pp. 91-94
Author(s):  
Zhen Hua Chen ◽  
Yong Qi Cheng ◽  
Wei Jun Xia ◽  
Hong Ge Yan ◽  
Ding Chen
Keyword(s):  
Magnesium Alloy ◽  
Rolling Direction ◽  
Annealing Treatment ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Magnesium Alloy Sheet ◽  
Optical Microstructure ◽  
Az31 Magnesium Alloy Sheet

In order to improve the formability of AZ31 magnesium alloy sheet at room temperature, a new process, so-called equal channel angular rolling (ECAR) and followed by annealing treatment was applied to process the sheet. The optical microstructure of the as-received sheet was similar with that of the ECARed one after annealing treatment, the Erichsen value and limiting drawing ratio of the ECARed sheet was about 6.26mm and 1.6, respectively, which was much larger than that of 4.18mm and 1.2 for the as-received sheet. These can be attributed to the low yield ratio and high strain hardening exponent due to the modified texture induced by the shear deformation during ECAR process, which is favor of the activations of basal slipping and twinning at ambient temperature, especially deforming at the rolling direction.

Forming Behaviour at Elevated Temperature of a Laser Heat-Treated AZ31 Magnesium Alloy Sheet

2018 ◽  
Vol 941 ◽  
pp. 1270-1275
Author(s):  
Donato Sorgente ◽  
Gianfranco Palumbo ◽  
Alessandro Fortunato ◽  
Alessandro Ascari ◽  
Ali Arslan Kaya
Keyword(s):  
Magnesium Alloy ◽  
Heat Input ◽  
Elevated Temperatures ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Dome Height ◽  
Magnesium Alloy Sheet ◽  
Laser Heat ◽  
Az31 Magnesium Alloy Sheet ◽  
Forming Behaviour

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.

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