Geometrically necessary twins in bending of a magnesium alloy

McClelland, Z.; Li, B.; Horstemeyer, S.J.; Brauer, Shane A.; Adedoyin, Adetokunbo; Hector, Louis G.; Horstemeyer, M.F.

doi:10.1016/j.msea.2015.08.027

Cited by 33 publications

(12 citation statements)

References 39 publications

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“…While, for base bending, the stress condition exactly was opposite, that is, the top region of joint was subjected to extension and bottom region was subjected to compression along TD. The {1012} <1011> twinning is favorable when a tensile stress is applied along the c-axis of the hexagonal lattice [13]. Through comparing Figures 6 and 2b can be seen that the concave appearances formed in the regions with abundant twins.…”

Section: Microstructure Evolution Of Surface Test Sample and Base Tesmentioning

confidence: 92%

“…It is well known that {1012} <1011> extension twinning and {1011} <1012)> contraction twinning are two important deformation mechanisms for hcp Mg alloys at room temperature [12,13]. The activity of extension twinning and contraction twinning are related to grain orientation and loading condition, as well as c/a ratio (γ) of Mg alloys [13,14]. It has been widely reported that the {1012} <1011> system is the most commonly twinning mode in all hcp metals [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

“…The {1012} <1011> twinning is most favorable when a tensile stress is parallel to the c-axis of the Mg crystal. On the contrary, it is suppressed when a compressive stress is parallel to the c-axis or a tensile stress is perpendicular to the c-axis [13]. Therefore, the twinning mechanism may be complicated under different stress condition of FSWed Mg alloy joint with different texture distribution.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Activation and Evolution of Twinning during Bending of Friction Stir Welded AZ31 Magnesium Alloys

Qin

Zheng

2020

Metals

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AZ31 magnesium alloy joints obtained by friction stir welding with rotation speed of 1400 rpm and welding speed of 200 mm/min were subsequently subjected to the three-point bending process. The bending behavior, microstructure evolution and twinning mechanism were investigated. The results indicate that the stress-strain curve appeared as power-law shape during tension and the stress-strain curve appeared as work hardening shape during compression. However, the stress-strain curve during bending is different and macrographs of face and base bending indicated that the severe strain localization was present during bending of FSWed AZ31 magnesium alloy joint. Three concave regions formed due to texture distribution and stress state in the weld zone. In those regions, the grains had favorable orientation with c-axis parallel to the direction of tensile stress and abundant twins were activated. It can be proved by electron backscatter diffraction (EBSD) analysis—two twinning mechanisms were activated during bending—that is, ~56° { 10 1 ¯ 1 } contraction twin and ~86° { 10 1 ¯ 2 } expansion twin, in which { 10 1 ¯ 2 } twinning was main plastic deformation mechanism of joint and the number of twins was proportional to the compressive stress in corresponding areas. The twinning resulted in lattice rotation about 86° around < 1 2 ¯ 10 > direction and changed the orientation distribution of original crystal.

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Section: Microstructure Evolution Of Surface Test Sample and Base Tesmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Activation and Evolution of Twinning during Bending of Friction Stir Welded AZ31 Magnesium Alloys

Qin

Zheng

2020

Metals

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“…McClelland et al [12]; Niezgoda et al [13]; Shi et al [14]; Stanford et al [15]; Steglich et al [16]; Wang and Choo [17]; Wen et al [18]; Wu et al [19]; Xin et al [20]). In Mg alloys, the most commonly observed twinning mode is the   1 1 10 } 2 1 10 { extension twinning.…”

Section: Introductionmentioning

confidence: 99%

On the rapid hardening and exhaustion of twinning in magnesium alloy

Guo

Qiao

et al. 2017

Acta Materialia

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We numerically study the rapid hardening and possible role of exhaustion of twinning in magnesium alloys under twinning dominated conditions, based on the large strain elastic visco-plastic self-consistent model. It is found that upon the exhaustion of the tensile twinning, further deformation requires the material to activate Prismatic and Pyramidal slips, which have relative high critical resolved shear stress (CRSS). However, the stress level at the exhaustion of the tensile twinning is not high enough to activate Prismatic and Pyramidal slips. Consequently, the imposed strain increments must mainly be accommodated by elastic deformations, and the strain hardening rate becomes a large fraction of the elastic modulus. Therefore, it can be concluded that the rapid hardening is a composite response more associated with elasticity of a large volume fraction of the material, than the dislocation-dislocation interactions normally held responsible for strain hardening of metals.

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“…The poor workability stems mainly from difficulties with homogeneous deformation due to the lack of independent slip modes. The main plastic deformation modes observed in Mg and its alloys are hai dislocations and f1 0 1 2g twins [5,6], and some Mg alloys exhibit f1 0 1 1g twins in certain cases [7,8]. The motion of hai dislocations on the basal plane is known to be dominant under plastic deformation in Mg.…”

Section: Introductionmentioning

confidence: 99%