Assessment in predictability of visco-plastic self-consistent model with a minimum parameter approach: Numerical investigation of plastic deformation behavior of AZ31 magnesium alloy for various loading conditions

Abstract Based on the stress characteristics of the instantaneous cross-section deformation of the wall reducing section during the cold rolling of two-roll Pilger pipes, the rectangular samples with 0° and 90° to the extrusion direction (ED) were cut from the extruded AZ31 magnesium alloy bar for 3% pre-deformation test to simulate its stress state equivalently. The sample was then cut from the pre-deformed sample by wire cutting for secondary compression, and the sample that is not pre-deformed is selected. The mechanical behavior and texture evolution of AZ31 magnesium alloy under different loading conditions were respectively studied by EBSD experiment and VPSC simulation. Results show that the true stress–strain curve and texture evolution characteristics of AZ31 magnesium alloy during the secondary compression process are in good agreement with the prediction of the VPSC model. The secondary compression behavior can be effectively explained by the relative activity of the deformation modes. The pre-deformation in the ∥ED (⊥ED) direction is conducive to the shift of the pole density of the {0001} basal surface texture to the positive and negative directions of the ED (TD). The pre-deformed sample exhibits a higher yield strength than the non-pre-deformed sample in the same loading direction. The high ductility of magnesium alloys can be achieved by activating pyramidal 〈c + a〉 slippage.

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Numerical Investigation of Secondary Deformation Mechanisms on Plastic Deformation of AZ31 Magnesium Alloy Using Viscoplastic Self-Consistent Model

Metals ◽

10.3390/met9010041 ◽

2019 ◽

Vol 9 (1) ◽

pp. 41 ◽

Cited By ~ 3

Author(s):

Yong Lian ◽

Li Hu ◽

Tao Zhou ◽

Mingbo Yang ◽

Jin Zhang

Keyword(s):

Plastic Deformation ◽

Magnesium Alloy ◽

Uniaxial Tension ◽

Pole Figure ◽

Mechanical Response ◽

Texture Evolution ◽

Deformation Mechanisms ◽

Az31 Magnesium Alloy ◽

Secondary Deformation ◽

Self Consistent

Uniaxial tension and compression of AZ31 magnesium alloy were numerically investigated via the viscoplastic self-consistent (VPSC) model to shed a light on the effect of secondary deformation mechanisms (prismatic <a> slip, pyramidal <c+a> slip, and { 10 1 ¯ 1 } contraction twinning) during plastic deformation. The method adopted in the present study used different combinations of deformation mechanisms in the VPSC modeling. In terms of the pyramidal <c+a> slip, it served as the first candidate for sustaining the extra plastic strain during the plastic deformation. The improvement of activity in the pyramidal <c+a> slip contributed to the increase in the mechanical response and the splitting of pole densities in { 0002 } pole figure during uniaxial tension. As for the prismatic <a> slip, its increasing activity was not only conducive to the improvement of flow stress in mechanical response, but also responsible for the splitting of pole densities in { 0002 } pole figure during uniaxial compression. With respect to the { 10 1 ¯ 1 } contraction twinning, it had a negligible influence on the plastic deformation of AZ31 magnesium alloy in terms of the mechanical response as well as the slip and the twinning activities. However, it is better to include the { 10 1 ¯ 1 } contraction twinning in the VPSC modeling to more accurately predict the texture evolution.

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