Influence of texture on Hall–Petch relationships in an Mg alloy

Wang, Yi; Choo, Hahn

doi:10.1016/j.actamat.2014.08.023

Cited by 339 publications

(73 citation statements)

References 77 publications

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“…2, five different specimen orientations with tilt angles of D =0°, 30°, 45°, 60° and 90° between the ND and loading direction (LD) were used to study the mechanical anisotropy under uniaxial tension. These tests are very similar to those carried out by Wang and Choo [31] on samples with different mean grain sizes in the range of 26 ~127 μm.…”

Section: Resultssupporting

confidence: 82%

On twinning and anisotropy in rolled Mg alloy AZ31 under uniaxial tension

et al. 2016

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Abstract. The Elastic Visco-Plastic Self-Consistent (EVPSC) model, with the recently developed Twinning and DeTwinning (TDT) description, is applied to study the mechanical behaviour of hot-rolled Mg alloy AZ31 under uniaxial tension. Numerical results are compared to the experimental uniaxial tensile tests reported earlier by Chapuis et al. [29] for the out-of-plane directions of a thick plate along angles of α=0°, 30°, 45°, 60° and 90° between the normal direction and longitudinal specimen axis. It is shown that accounting for the initial texture and calibrating the EVPSC-TDT model by using uniaxial tension tests along the rolling direction and normal direction permits prediction of the strength anisotropy and strain hardening behavior along all five tensile directions, i.e. for cases in which the contribution of twinning is dominating, negligible or intermediate.

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Section: Resultssupporting

confidence: 82%

On twinning and anisotropy in rolled Mg alloy AZ31 under uniaxial tension

et al. 2016

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“…It is revealed that the stress concentration along the grain boundaries triggers the nucleation of twins and, thus, the nucleation density of twins is sensitive to the grain size. Additionally, the size of twins is limited by grain size, which implies that grain size affects twin growth [15]. Figure 3b,d reveal that the number density and size of twins increase significantly as the strains rise from 2% to 10%.…”

Section: Methodsmentioning

confidence: 84%

“…Moreover, basal plane slip takes a high proportion during cold deformation in random orientated alloys [15,17]. That is why the density of dislocations and twins becomes pronounced when the specimen subjected to plastic pre-stretching deformation.…”

Section: Effect Of Pre-stretching On the Precipitation Evolutionmentioning

confidence: 99%

Enhanced Age Strengthening of Mg-Nd-Zn-Zr Alloy via Pre-Stretching

Guo

Zhao

Wang

et al. 2016

Metals

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Pre-stretching was carried out to modify the microstructure of Mg-Nd-Zn-Zr alloy to enhance its age strengthening. The results indicated that more heterogeneous nucleation sites can be provided by the high density of dislocations caused by the plastic pre-stretching deformation, as well as speeding up the growth rate of precipitates. Comparison of microstructure in non-pre-stretched specimens after artificial aging showed that pre-stretched specimens exhibited a higher number density of precipitates. The fine and coarse plate-shaped precipitates were found in the matrix. Due to an increase in the number density of precipitates, the dislocation slipping during the deformation process is effectively hindered, and the matrix is strengthened. The yield strength stabilizes at 4% pre-stretching condition, and then the evolution is stable within the error bars. The 8% pre-stretched specimens can achieve an ultimate tensile strength of 297 MPa. However, further pre-stretching strains after 8% cannot supply any increase in strength. Tensile fracture surfaces of specimens subjected to pre-stretching strain mainly exhibit a trans-granular cleavage fracture. This work indicated that a small amount of pre-stretching strain can further increase strength of alloy and also effectively enhance the formation of precipitates, which can expand the application fields of this alloy.

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“…Although it is not examined in detail within the present research, the possibility of short range ordering of solute is of interest, especially as it pertains to operation of the twinning modes (Nie et al, 2013). Other factors such as grain size also have a significant effect on the slip and twinning behavior (Barnett et al, 2004;Wang and Choo, 2014).…”

Section: Mg Alloysmentioning

confidence: 99%

“…The total strength based on the single crystal (∞), the EPSC CRSS values for T3 material and EPSC CRSS from Stanford et al, (2014) are highlighted in grey (all values in MPa). When two values appear separated by commas, the first is based on HP coefficient of Wang and Choo (2014) and the second is based on Table 3.3: The effect of grain size on individual deformation modes obtained using Hall Petch coefficients Wang and Choo (2014) and …”

Section: List Of Figuresmentioning

confidence: 99%

Quasi-static and Dynamic Constitutive Behavior of Precipitate Strengthened Al and Mg Alloys: An Experimental and Crystal Plasticity Modeling Investigation

Bhattacharyya¹

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A present challenge in material science lies in applying the knowledge of single crystal level deformation behavior to predict the polycrystalline response. Mean field polycrystal plasticity models such as Elasto-Plastic Self-Consistent (EPSC) and Visco-Plastic SelfConsistent (VPSC) models provide computationally efficient tools to link the single crystal response to the polycrystal aggregate.Many commercial alloys are precipitation hardenable, and the introduction of second phase particles in the matrix leads to an increase in strength and changes the work hardening behavior. Besides affecting the uniaxial flow behavior, the precipitates also alter the anisotropy of the material. The flow response and anisotropy of two commercial precipitation-hardenable alloys were measured experimentally, as well as modeled and predicted using the crystal plasticity approach.In the first part of the dissertation, EPSC modeling was employed to describe the flow behavior, anisotropy and texture evolution of Mg alloy WE43 in the T5 (hot worked and artificially peak aged) temper, which has recently been proposed as a potential lightweight metallic armor. The independent contribution of texture, grain size and various strengthening mechanisms were determined and their impact on individual slip modes was quantified.Additionally, the strain rate sensitivities of each individual mode were determined. The results show that deformation twinning and basal slip can be treated as rate insensitive at least up to the strain rate regime investigated here. The modeling efforts led to the development of a set of parameters which were then validated using data obtained from T3 and T6 tempered samples which possessed microstructures which were far from that of the material used to develop the model. Furthermore, the aging response and the fracture behavior of this alloy was explored and it was established that the T5 temper has the optimum combination of strength and ductility. The results confirm the notion that the poor ageing hardening characteristics of WE43, as compared to Al alloys, is due to a low number density/volume fraction of the strengthening phases.The second part of the dissertation focuses on modeling the homogenous deformation response of Al-7085 alloy, a new high strength precipitation hardenable alloy which is used for aerospace applications and has also been considered as a lightweight metallic armor. First, the texture evolution and large strain behavior was measured and then modeled using the VPSC code, which permitted the role of latent hardening and grain shape effects to be explored. These initial experimental modeling results highlighted the potential importance of 'backstresses' generated by non-shearable precipitates. To account for this, a micromechanical model of kinematic hardening was implemented within the EPSC framework. This modified EPSC model was then used to predict the flow stress and strain anisotropy of this alloy in various tempers.The results demonstrate that incorporation of precipitate-induced...

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Influence of texture on Hall–Petch relationships in an Mg alloy

Cited by 339 publications

References 77 publications

On twinning and anisotropy in rolled Mg alloy AZ31 under uniaxial tension

On twinning and anisotropy in rolled Mg alloy AZ31 under uniaxial tension

Enhanced Age Strengthening of Mg-Nd-Zn-Zr Alloy via Pre-Stretching

Quasi-static and Dynamic Constitutive Behavior of Precipitate Strengthened Al and Mg Alloys: An Experimental and Crystal Plasticity Modeling Investigation

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