An experimental study of cyclic deformation of extruded AZ61A magnesium alloy

Zhang, Jixi; Yu, Qin; Jiang, Yanyao; Li, Qizhen

doi:10.1016/j.ijplas.2010.09.004

Cited by 132 publications

(84 citation statements)

References 82 publications

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“…To accommodate arbitrary deformation under mechanical loading, {1 0 1 2}h1 0 1 1i twins are commonly activated at room temperature [7][8][9][10][11][12]. However, the localized shear associated with twinning is partly behind the low ductility and the poor deformability of Mg alloys [13][14][15][16][17]. In addition, the presence of twin boundaries (TB) causes a crystallographic discontinuity of slip systems across TB.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of energy and atomic solubility of twinning-associated boundaries in hexagonal metals

2015

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Twinning-associated boundaries (TB), f1 0 1 ng coherent twin boundaries (CTB) and the coherent basal-prismatic (CBP) boundary in six hexagonal metals (Cd, Zn, Mg, Zr, Ti and Be) are studied using first-principles density function theory, with the focus on the structural character of TB and the solute's solubility at TB. Regarding the structure and energy of TB, the formation of TB is associated with the creation of an excess volume. All six metals show positive excess volume associated with ð1 0 1 1Þ and ð1 0 1 3Þ CTB, but the excess volume associated with ð1 0 12Þ CTB and CBP can be positive or negative, depending on the metal. The ð1 0 1 2Þ CTB has higher excess energy than ð1 0 1 1Þ and ð1 0 1 3Þ CTB for metals with c=a < ffiffiffiffiffiffiffi ffi 8=3 p , but lower for metals with c=a > ffiffiffiffiffiffiffi ffi 8=3 p . More interestingly, CBP has lower excess energy than ð1 0 1 2Þ CTB for all metals. This is consistent with the recent finding concerning the pure-shuffle nucleation mechanism of ð1 0 1 2Þ twins. To understand solubility at TB, the solubility of solute atoms in Mg, Ti and Zr is calculated for solute positions in bulk, ð1 0 1 2Þ CTB and CBP boundaries. In general, solute atoms have better solubility at CTB and CBP than in bulk. Interestingly, the solubility of solute atoms changes linearly with normal strain at CBP, increasing with normal strain for solute atoms with a greater metallic radius than the matrix, and decreasing with normal strain for solute atoms with a smaller metallic radius than the matrix. This suggests that the distribution of solute atoms in bulk, CTB and CPB boundaries varies with stress state and, in turn, affects the mobility of TB.

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Section: Introductionmentioning

confidence: 99%

First-principles study of energy and atomic solubility of twinning-associated boundaries in hexagonal metals

2015

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“…On the contrary, limited investigations have been conducted to analyse multiaxial cyclic behaviour of magnesium alloys. Zhang et al [25] performed multiaxial experiment on AZ61A extrusions. They observed mechanical twinning at large shear strain amplitudes.…”

Section: Introductionmentioning

confidence: 99%

Multiaxial effects on LCF behaviour and fatigue failure of AZ31B magnesium extrusion

Albinmousa

Jahed

2014

International Journal of Fatigue

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“…The stress-strain response, texture evolution, and microstructure evolution under cyclic loading and non-proportional loading paths have been extensively studied using experiment and modeling. [2][3][4][5][6] Twinning and de-twinning are recognized to play crucial roles in developing the asymmetric stress-strain hysteresis loop, texture evolution, and initiation of fracture. [3,5,7] In properly oriented single crystals, multiple twins can be activated and interact with each other.…”

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confidence: 99%

“…As a consequence, their interaction and reactions develop a characteristic locked 'quilted looking' twinning structure (Figure 1(a)) which affects subsequent twinning and de-twinning, causes twinning-induced hardening, and potentially results in crack initiation. [3][4][5][6][7] Jiang et al [8] and Yang and Zhang [9] reported that different twin variants and twin-twin intersections are associated with the deformation stage with a higher strain hardening rate in AZ31 Mg alloy which is subjected to compression along the extrusion direction. Ma et al [10] and Oppedal et al [11] found that multivariants are activated to accommodate large straining and the subsequent twin-twin interaction contributes to a significant strain hardening.…”

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confidence: 99%