Room Temperature Formability of Mg Alloys

2009 ◽  
Vol 618-619 ◽  
pp. 463-466 ◽  
Author(s):  
Dae H. Kang ◽  
D.W. Kim ◽  
S. Kim ◽  
Geun Tae Bae ◽  
K.H. Kim ◽  
...  
Keyword(s):  
Work Hardening ◽  
Room Temperature ◽  
Mg Alloys ◽  
Dome Height ◽  
Hardening Behavior ◽  
Erichsen Cupping Test ◽  
Twin Roll Cast ◽  
Twin Roll ◽  
Work Hardening Exponent ◽  
Ldh Value

Room temperature formability of twin-roll cast Mg alloys has been investigated and correlated with their work hardening behavior. Tensile properties of these alloys were measured and their work hardening behaviour was analysed by using constitutive equations. Room temperature formability of the alloys was evaluated by the limiting dome height (LDH) value, obtained by the Erichsen cupping test. It shows that there is a linear relationship between LDH value and the inverse of yield ratio, which is a function of work hardening exponents. An increase in grain size increases work hardening exponent and concurrently increases LDH.

Relationship between stretch formability and work-hardening capacity of twin-roll cast Mg alloys at room temperature

2009 ◽  
Vol 61 (7) ◽  
pp. 768-771 ◽  
Author(s):  
D.H. Kang ◽  
D.-W. Kim ◽  
S. Kim ◽  
G.T. Bae ◽  
K.H. Kim ◽  
...  
Keyword(s):  
Work Hardening ◽  
Room Temperature ◽  
Mg Alloys ◽  
Stretch Formability ◽  
Twin Roll Cast ◽  
Twin Roll

Method for the Depletion of the Basal Texture in Rolled AZ31 Magnesium Sheets

2014 ◽  
Vol 783-786 ◽  
pp. 478-484
Author(s):  
Christian Schmidt ◽  
Rudolf Kawalla
Keyword(s):  
Room Temperature ◽  
Basal Texture ◽  
Final Thickness ◽  
Cold Forming ◽  
Texture Change ◽  
Boundary Rotation ◽  
Different Temperatures ◽  
Cast Magnesium ◽  
Twin Roll Cast ◽  
Twin Roll

The deformation and hardening mechanisms of magnesium usually lead to a typical basal orientation of crystals during a production of sheets by forming techniques. The basal texture related anisotropic property behavior and especially the further decrease in formability at room temperature is disadvantageous and undesired for subsequent rolling and final forming processes.The objective of this work is to find methods to improve these texture-related properties and the cold forming ability of magnesium sheets. Firstly, rolling at different temperatures and pass reductions, with the goal of weakening the basal texture component in semi-finished products is investigated, based on the advantageous initial texture and microstructure of twin-roll-cast (TRC) magnesium strips. In this context, texture and microstructure development is examined after a particular multi-pass rolling and heat treatment processes. Twin-roll-cast magnesium strips of alloy AZ31, with an initial thickness of 4.5 mm, rolled to a final thickness of 1.2 mm, are used as feedstock.Secondly, a new thermo-mechanical magnesium strip treatment has been developed in order to completely disintegrate the basal texture and intentionally generate only non-basal orientations with high Schmid-factors for the easy-to-activate basal slip systems. This process, which is designed as a final strip treatment, has been investigated regarding its texture change effect on rolled 1.2 mm AZ31 sheets, which also originate from TRC feedstock.It has clearly been found that the developed rolling technology for TRC feedstock leads to a significantly reduced basal texture due to grain boundary rotation and recrystallization at those rotated regions. The application of the separately developed strip treatment effects a complete elimination of the basal texture in a large volume of the sheet. Applying both technologies on magnesium sheets results in a tremendous increase in formability at room temperature as a consequence of the altered texture.

Mechanical Properties of Twin Roll Cast AZ91 Magnesium Alloy at Room Temperature

2007 ◽  
Vol 26-28 ◽  
pp. 145-148 ◽  
Author(s):  
Shu Hei Uchida ◽  
Ippei Takeuchi ◽  
Gentaro Gonda ◽  
Kinji Hirai ◽  
Tokuteru Uesugi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Cast Alloy ◽  
Casting Process ◽  
Az91 Magnesium Alloy ◽  
Die Cast ◽  
Az91 Magnesium ◽  
Twin Roll Cast ◽  
Twin Roll

Twin roll casting process combines casting and hot rolling into a single process. In this study, mechanical properties at room temperature and microstructure of the twin roll cast AZ91 magnesium alloy are investigated. The alloy exhibited a good combination of high ultimate strength of 343MPa, yield stress of 224MPa and elongation to failure of 13%. The mechanical property was very excellent compared with AZ91 die-cast alloy. EPMA analysis reveals that the Al concentration in Mg matrix is higher in twin roll cast alloy than that in die-cast alloy. This high Al concentration must be the origin of the good mechanical properties of twin roll cast alloy at room temperature.

Mechanical Properties of Twin Roll Cast AZ91 Magnesium Alloy at Room Temperature

2007 ◽  
pp. 145-148 ◽  
Author(s):  
Shu Hei Uchida ◽  
Ippei Takeuchi ◽  
Gentaro Gonda ◽  
Kinji Hirai ◽  
Tokuteru Uesugi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium ◽  
Twin Roll Cast ◽  
Twin Roll

PLASTICITY OF IRON SINGLE CRYSTALS

1967 ◽  
Vol 45 (2) ◽  
pp. 1101-1120 ◽  
Author(s):  
A. S. Keh ◽  
Y. Nakada
Keyword(s):  
Temperature Dependence ◽  
Single Crystals ◽  
Work Hardening ◽  
Room Temperature ◽  
Proportional Limit ◽  
Single Slip ◽  
Hardening Behavior ◽  
The Past ◽  
Temperature Dependences ◽  
Latent Hardening

Results accumulated in the past four years on the plastic deformation of iron single crystals are summarized.The work-hardening behavior of iron single crystals depends very much on orientation and temperature. At room temperature, three-stage hardening was observed for single-slip orientations. The work-hardening rates in stages I and II were correlated with the extent of localized secondary slip.Latent hardening was observed in iron crystals. The latent-hardening ratio is about 1.3 and is relatively independent of temperature and choice of latent system.The yield stress of iron single crystals is very dependent on temperature and is also sensitive to orientation at low temperatures and to interstitial content at all temperatures. By adding interstitials to purified crystals, the athermal portion of the flow stress of iron is raised, but its temperature dependence is not altered. Crystals oriented for single slip on the (101) and (112) planes have different temperature dependences of the proportional limit. Similar but small differences in this temperature dependence of proportional limits were observed in crystals oriented for single, double, and multiple slip on {112} planes. These results are explained on the basis of a Peierls mechanism.

Modeling Cold-Rolling Processes of Commercial Twin Roll Cast Aluminum Alloys

2000 ◽  
Vol 123 (2) ◽  
pp. 149-154 ◽  
Author(s):  
E. S. Puchi-Cabrera
Keyword(s):  
Aluminum Alloys ◽  
Work Hardening ◽  
Design Procedure ◽  
Compression Tests ◽  
Cast Aluminum ◽  
Final Thickness ◽  
Rolling Pass ◽  
Rolling Load ◽  
Twin Roll Cast ◽  
Twin Roll

Primary rolling operations of twin-roll cast commercial aluminum alloys can be designed more efficiently on the basis of maintaining a constant rolling load throughout the rolling program. The computation of the final thickness of the strip for every pass can be conducted by means of the simplified theory of Bland and Ford, assuming a constant rolling load during the rolling schedule. Particularly, for twin-roll cast Al-1 percent Mn alloy (TRC 3003) it is possible to reduce one rolling pass if the rolling load is kept constant at about 800 ton. The implementation of this design procedure requires a knowledge of both the work-hardening characteristics of the material and the change in friction conditions throughout the operation. For this last purpose, von Ka´rma´n linear differential equation can be integrated following a more efficient computational procedure based on integrating factors and standard numerical integration methods. Also, the work-hardening characteristics of the material were determined from plane strain compression tests, on the basis of the evolution laws proposed by Sah et al. and Follansbee and Kocks. The rolling pass design that has been proposed could have clear advantages in terms of the productivity of the mill, quality of the rolled products and extension of the rolls life.

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