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

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.

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Effect of strain path change on the texture evolution after cold rolling and recrystallization of Nickel-40 wt. %Cobalt alloy

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/375/1/012018 ◽

2018 ◽

Vol 375 ◽

pp. 012018 ◽

Cited By ~ 1

Author(s):

Gyan Shankar ◽

Satyam Suwas

Keyword(s):

Cold Rolling ◽

Strain Path ◽

Texture Evolution ◽

Cobalt Alloy ◽

Strain Path Change

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In-situ study of strain and texture evolution during continuous strain path change

10.25518/esaform21.2168 ◽

2021 ◽

Author(s):

Sisir Dhara ◽

Scott Taylor ◽

Łukasz Figiel ◽

Darren Hughes ◽

Barbara Shollock ◽

...

Keyword(s):

Strain Path ◽

Texture Evolution ◽

Test Method ◽

Image Correlation ◽

Field Strain ◽

Correlation Technique ◽

Full Field ◽

Multi Stage ◽

Experimental Apparatus ◽

Strain Path Change

Automotive stamping is a multi-stage process where a sheet material is drawn in first stage and then redrawn, flanged and pierced in subsequent stages. In the first draw stage, continuous strain path change is induced in the material while a discontinuous strain path change occurs when the material is processed in the subsequent stages of a multi-stage stamping operation. The strain path transition can potentially alter the forming limit of the material. Previous research has investigated the effect of the discontinuous mode of strain path change by loading the sample in one strain path, unloading it, then reloading it in a second path. Thus, discontinuous strain path change was obtained. In this work, the effect of continuous strain path change was investigated with a novel experimental design that allowed cruciform samples to change strain path continuously without unloading. The work was carried out in two stages. In the first stage, the design of the cruciform sample was verified with finite element modelling to ensure the occurrence of continuous strain path change and this was validated experimentally using DX54 material by capturing full-field strain measurements data using digital image correlation technique. The size of the experimental apparatus permitted it to be placed inside a scanning electron microscope chamber. In the second stage, the validated test method was used to evaluate microstructural changes during the deformation including full-field strain and texture evolution. The micro-strain evolution showed rotation of strain bands while the texture evolution conveyed grain rotation during continuous strain path change.

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