scholarly journals Mechanical Anisotropy Induced by Strain Path Change for AZ31 Mg Alloy Sheet

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1049
Author(s):  
Chong Yang ◽  
Yibing Mei ◽  
Dan Meng ◽  
Guoguo Zhu ◽  
Shengwei Liu ◽  
...  
Keyword(s):  
Yield Strength ◽  
Strain Path ◽  
Texture Evolution ◽  
Rolling Direction ◽  
Mechanical Anisotropy ◽  
Heterogeneous Distribution ◽  
Az31 Sheet ◽  
Strain Paths ◽  
Strain Path Change ◽  
Strain Path Changes

The variation of strain paths induces anisotropy during practical sheet forming processes, which is very important for the subsequent processing technology of anisotropic Mg alloys. In this study, two-step loading tests (tension-tension) were performed to clarify the effect of strain path changes on the evolution of anisotropy on rolled AZ31 sheet. Specimens were preloaded with tension along the rolling direction (RD) with 9% of prestrain. Then, second tension was conducted along 0°, 30°, 45°, 60° and 90° from the RD. It was found that yield strength during the second loading increased along the same direction compared to uniaxial tension without prestraining. For the second loading, the yield strength and flow stress decreased with the increase of the angle from the RD. It was found that the strain path change resulted in stronger anisotropy than that induced by texture. Moreover, it was found that the main deformation modes were basal and prismatic slips during the second loading based on visco-plastic self-consistent (VPSC) modeling. The relative activities of basal and prismatic slips were affected by the second loading direction due to texture evolution. The mechanical anisotropy induced by strain path changes was ascribed to the coupling of the heterogeneous distribution of dislocations and texture evolution induced by prestraining.

A Theoretical Study of the Effect of the Double Strain Path Change on the Forming Limits of Metal Sheet

2013 ◽  
Vol 554-557 ◽  
pp. 127-138 ◽  
Author(s):  
Marilena Butuc ◽  
Frédéric Barlat ◽  
José Grácio ◽  
Gabriela Vincze
Keyword(s):  
Sheet Metal ◽  
Strain Path ◽  
Theoretical Study ◽  
Alloy Sheet ◽  
Initial Shape ◽  
Forming Limits ◽  
Remarkable Effect ◽  
Strain Paths ◽  
Strain Path Change ◽  
Strain Path Changes

The present paper aims at a theoretical study of the forming limits of a sheet metal subjected to double strain path changes by using as reference material the AA6016-T4 aluminum alloy sheet. The simulation of plastic instability is carried out through the Marciniak-Kuczynski analysis. The initial shape of the yield locus is given by the Yld2000-2d plane stress yield function. The strain hardening of the material is described by the Voce type saturation law. Linear and several complex strain paths involving single and double strain path changes are taken into account. The validity of the model is assessed by comparing the predicted and experimental forming limits under linear and selected one strain path change. A good accuracy of the developed software on predicting the forming limits is found. A sensitive analysis of the influence of the type and value of the double prestain in the occurrence of the plastic flow localization is performed. A remarkable effect of the double strain path change on the sheet metal forming limits is observed.

Orientation and Path Dependence of Formability in the Stress- and the Extended Stress-Based Forming Limit Curves

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
C. Hari Manoj Simha ◽  
Kaan Inal ◽  
Michael J. Worswick
Keyword(s):  
Strain Path ◽  
Path Dependence ◽  
Forming Limit ◽  
Stress Space ◽  
Forming Limit Diagrams ◽  
Metall Trans ◽  
Strain Paths ◽  
Strain Path Changes ◽  
Path Dependent ◽  
Forming Limit Curves

This article analyzes the formability data sets for aluminum killed steel (Laukonis, J. V., and Ghosh, A. K., 1978, “Effects of Strain Path Changes on the Formability of Sheet Metals,” Metall. Trans. A., 9, pp. 1849–1856), for Al 2008-T4 (Graf, A., and Hosford, W., 1993, “Effect of Changing Strain Paths on Forming Limit Diagrams of Al 2008-T4,” Metall. Trans. A, 24A, pp. 2503–2512) and for Al 6111-T4 (Graf, A., and Hosford, W., 1994, “The Influence of Strain-Path Changes on Forming Limit Diagrams of Al 6111 T4,” Int. J. Mech. Sci., 36, pp. 897–910). These articles present strain-based forming limit curves (ϵFLCs) for both as-received and prestrained sheets. Using phenomenological yield functions, and assuming isotropic hardening, the ϵFLCs are transformed into principal stress space to obtain stress-based forming limit curves (σFLCs) and the principal stresses are transformed into effective stress and mean stress space to obtain the extended stress-based forming limit curves (XSFLCs). A definition of path dependence for the σFLC and XSFLC is proposed and used to classify the obtained limit curves as path dependent or independent. The path dependence of forming limit stresses is observed for some of the prestrain paths. Based on the results, a novel criterion that, with a knowledge of the forming limit stresses of the as-received material, can be used to predict whether the limit stresses are path dependent or independent for a given prestrain path is proposed. The results also suggest that kinematic hardening and transient hardening effects may explain the path dependence observed in some of the prestrain paths.

Texture evolution of rolled Mg–3Al–1Zn alloy undergoing a {10-12} twinning dominant strain path change

2015 ◽  
Vol 646 ◽  
pp. 573-579 ◽  
Author(s):  
Sung Hyuk Park ◽  
Seong-Gu Hong ◽  
Jeong Hun Lee ◽  
Yong-Hak Huh
Keyword(s):  
Strain Path ◽  
Texture Evolution ◽  
Strain Path Change

Effect of Strain Path Change on Formability of TRIP Steels

2018 ◽  
Vol 920 ◽  
pp. 223-229
Author(s):  
Chi Zhou ◽  
Wen Tao Zhang ◽  
Sai Jun Zhang ◽  
Jun Jie Deng ◽  
Qin Xiang Xia
Keyword(s):  
Strain Path ◽  
Positive Impact ◽  
Rolling Direction ◽  
Total Elongation ◽  
Second Step ◽  
Strain Rates ◽  
Trip Steels ◽  
Localized Necking ◽  
Tension Tests ◽  
Strain Path Change

The effect of strain path change on formability of TRIP590 and TRIP780 was investigated experimentally. Two-step uniaxial tension tests, which consist of the first loading in the rolling direction (RD) and the second loading in the directions varied from RD to transverse direction (TD) in every 15º, were conducted. The evolution of strain rates inside and outside the localized necking zone were inspected by using DIC measuring technique. When the angle between the two loading directions was increased from 0º to 90 º, the subsequent hardening behavior in second step was transited from cross-loading type to Bauschinger type. The total elongation was increased when the two loading directions are close to each other and then it was decreased with the increase of angle. When the angle further increased to 90 º, the total elongation is increased again. It is believed that both of the martensite transformation and Bauschinger type transient has a positive impact on the formability of TRIP steels.

Mechanical behavior and texture evolution of aluminum alloys subjected to strain path changes: Experiments and modeling

2019 ◽  
Vol 757 ◽  
pp. 32-41 ◽  
Author(s):  
Xuanzhen Chen ◽  
Yong Peng ◽  
Chao Chen ◽  
Jiahao Li ◽  
Kui Wang ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Mechanical Behavior ◽  
Strain Path ◽  
Texture Evolution ◽  
Strain Path Changes
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