Influence of Temperature, Strain Rate, and Sheet Thickness on the Deformation Behaviour of Twin-Roll Cast, Rolled and Heat-Treated AZ31 under Uniaxial Loading

2016 ◽  
Vol 684 ◽  
pp. 29-34
Author(s):  
Franz Berge ◽  
Markus Wollschläger ◽  
Christina Krbetschek ◽  
Madlen Ullmann
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Deformation Behaviour ◽  
Sheet Thickness ◽  
Influence Of Temperature ◽  
Heat Treated ◽  
Elongation To Failure ◽  
Twin Roll Cast ◽  
Twin Roll ◽  
Temperature Strain

The influence of temperature, strain rate, and sheet thickness on the mechanical properties of twin-roll cast, rolled and heat-treated AZ31 was investigated under tensile loading from different directions (0°, 90°). To assess the forming behaviour of different sheet thicknesses (0.6 mm, 1 mm), tensile tests were performed with an electromechanical testing device between 20 °C and 300 °C at strain rates of 10−4 s−1 and 10−2 s−1. With rising temperature, the flow stress decreased while the elongation to failure (A80) increased, which may be related to the enhanced dislocation motion and the activation of additional nonbasal slip systems at T > 200 °C. It can be seen that the anisotropy of flow stress and elongation to failure was influenced by the temperature, the strain rate, and the sheet thickness.

scholarly journals The Effect of Sheet Thickness, Loading Rate and Punch Diameter on the Deformation Behaviour of AZ31 during 3-Point Bending

2016 ◽  
Vol 854 ◽  
pp. 65-72
Author(s):  
Franz Berge ◽  
Heiko Winderlich ◽  
Christina Krbetschek ◽  
Madlen Ullmann ◽  
Rudolf Kawalla
Keyword(s):  
Loading Rate ◽  
Deformation Behaviour ◽  
Testing Machine ◽  
Sheet Thickness ◽  
Bending Test ◽  
Bending Angle ◽  
Grain Sizes ◽  
Heat Treated ◽  
Twin Roll Cast ◽  
Twin Roll

In this study, the influence of sheet thickness, loading rate, and punch diameter on the bending behaviour of twin-roll cast, rolled and heat-treated AZ31 magnesium alloy was investigated. Therefore, the 3-point bending test was performed at room temperature using an electromechanical testing machine (v = 0.1−10 mm/s) with different punch diameters (D = 2 mm, 8 mm, 16 mm). The initial material has a recrystallized microstructure with grain sizes of 6−9 µm. It is shown by the mechanical investigations that the bending force increases with the sheet thickness. In contrast to this, the bending angle is independent of the sheet thickness. In addition, the punch diameter and the loading rate do not influence the maximum force and the bending angle significantly.

Influence of the Sheet Manufacturing Process on the Forming Limit Behaviour of Twin-Roll Cast, Rolled and Heat-Treated AZ31

2017 ◽  
Vol 746 ◽  
pp. 154-160 ◽  
Author(s):  
Thorsten Henseler ◽  
Madlen Ullmann ◽  
Rudolf Kawalla ◽  
Franz Berge
Keyword(s):  
Sheet Metal ◽  
Elevated Temperatures ◽  
Lightweight Design ◽  
Sheet Thickness ◽  
Forming Limit ◽  
Specific Strength ◽  
Heat Treated ◽  
Limit Behaviour ◽  
Twin Roll Cast ◽  
Twin Roll

In the age of lightweight design, magnesium alloys play an increasing role in weight reduction of transport vehicles. The specific strength compared to aluminium alloys and steel grades is superior, giving the material great potential in lightweight application. The automobile and aeronautic industry use sheet metals with minimum thicknesses, making research in this field very important. Successful sheet metal forming depends on various process parameters and material characteristics. Thus, the influence of sheet thickness on the forming limit behaviour of twin-roll cast, rolled and heat-treated AZ31 was investigated. Nakajima tests were performed on a hydraulic sheet metal testing device at elevated temperatures with various sheet thicknesses from 0.6 mm to 2.0 mm. The results show an increase in formability with rising temperatures for all sheets. Furthermore, changes in formability among the sheet thicknesses were linked to their divergent microstructures, which result from the different sheet manufacturing parameters.

Flow Stress and Elongation of Superplastic Deformation in La55Al25Ni20 Metallic Glass

1999 ◽  
Vol 601 ◽  
Author(s):  
Y. Kawamura ◽  
A. Inoue
Keyword(s):  
Flow Stress ◽  
Metallic Glass ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
Constant Strain Rate ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Elongation To Failure ◽  
Crosshead Velocity

AbstractWe have investigated the flow stress and elongation of superplastic deformation in a La55Al25Ni20 (at%) metallic glass that has a wide supercooled liquid region of 72 K before crystallization. The superplasticity that appeared in the supercooled liquid region was generated by the Newtonian viscous flow that exhibits the m value of unity. The elongation to failure was restricted by the transition of the Newtonian flow to non-Newtonian one and the crystallization during deformation. We succeeded in establishing the constitutive formulation of the flow stress in the supercooled liquid region. Its formulation was expressed very well by a stretched exponential function σflow=Dε exp(H*/RT) [1-exp(E/{ε exp(H**/RT)}0.82)]. Formulations describing the elongation to failure in constant-strain-rate and constant-crosshead velocity tests were, moreover, established. It was found from the simulation that the maximum elongation in the constant-strain-rate test reached more than 106% which was two orders of magnitude larger than that in the constant-crosshead-velocity test.

Improving Mechanical Properties of Twin-Roll Cast AZ31 by Wire Rolling

2021 ◽  
Vol 1016 ◽  
pp. 957-963
Author(s):  
Marie Moses ◽  
Madlen Ullmann ◽  
Rudolf Kawalla ◽  
Ulrich Prahl
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rolling Texture ◽  
Total Elongation ◽  
Roll Casting ◽  
Heat Treated ◽  
Heat Treated Condition ◽  
Set Up ◽  
Twin Roll Cast ◽  
Twin Roll

Since 2018, the institute of metal forming has been studying the novel twin-roll casting (TRC) of magnesium wire at the pilot research plant set up specifically for this purpose. Light microscopic and scanning electronic investigations were carried out within this work and show the unique microstructure of twin-roll cast AZ31 magnesium alloy with grain sizes of about 10 μm ± 4 μm in centre and 39 μm ± 26 μm near the surface of the sample. By means of a short heat treatment (460 °C/15 min), segregations can be dissolved and grain size changes in centre to 19 μm ± 12 μm (increase) and near the surface to 12 μm ± 7 μm (decrease). Further, the mechanical properties of the twin-roll cast and heat-treated wire were analysed by tensile testing at room temperature. By heat treatment, the total elongation could be increased by a third whereas the strength decreases slightly. In heat-treated state, no preferred orientation is evident. In addition to the twin-roll cast and the heat-treated condition, the rolled state was analysed. For this purpose, the twin-roll cast wire was hot rolled using an oval-square calibration. After hot rolling, a dynamic recrystallization and grain refinement of the twin-roll cast wire could be achieved. It can be seen, that an increase in strength as well as in total elongation occur after wire rolling. Beside this, a rolling texture is evident.

The influence of temperature, strain rate history and shock preloading in the region of phase transition for armco-iron

2003 ◽  
Vol 110 ◽  
pp. 761-766
Author(s):  
A. M. Bragov ◽  
S. Brichikov ◽  
G. T. Gray ◽  
E. Kozlov ◽  
A. K. Lomunov ◽  
...  
Keyword(s):  
Phase Transition ◽  
Strain Rate ◽  
Armco Iron ◽  
Influence Of Temperature ◽  
Temperature Strain

Effects of Temperature, Strain Rate and Grain Size on Superplastic Behavior of Magnesium

2012 ◽  
Vol 488-489 ◽  
pp. 27-34 ◽  
Author(s):  
Muhammad Waseem Soomro ◽  
Thomas Rainer Neitzert
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Superplastic Forming ◽  
Experimental Results ◽  
Superplastic Behavior ◽  
Influence Of Temperature ◽  
Effects Of Temperature ◽  
Temperature Strain

The influence of temperature, grain size and strain rate on superplasticity of magnesium is investigated. Different approaches are compared along with their experimental results to show the variation in the amount of superplasticity by varying above mentioned parameters. At room temperature magnesium alloys usually have poor formability but recent studies of some alloys such as ZE10, AZ31, AZ61 AZ60, AZ80 and AZ91 are pointing that by varying the temperature along with grain size and strain rate improved formability is possible or even superplastic forming of these alloys can be achieved to meet the demands of automotive, aircraft and other weight conscious industries.

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