Effect of precipitate shape and orientation on Orowan strengthening of non-basal slip modes in hexagonal crystals, application to magnesium alloys

Wang, Fulin; Bhattacharyya, Jishnu J.; Agnew, Sean R.

doi:10.1016/j.msea.2016.04.056

Cited by 152 publications

(31 citation statements)

References 21 publications

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“…The influence of the volume fraction, morphology, and habit plane of precipitates on the hardening of slip systems in Mg alloys has been well characterized and understood in terms of both experiments and theoretical analysis [21][22][23]. In Mg alloys, common precipitate types are plates on the basal plane in Mg-Al alloy systems, rods with long axis being parallel to the c-axis of the matrix in Mg-Zn alloy series, and plates on the {1 0 1 0} prismatic planes in Mg-RE (rare earth) alloy systems [22].…”

Section: Introductionmentioning

confidence: 99%

On the interaction of precipitates and tensile twins in magnesium alloys

et al. 2019

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Although magnesium alloys deform extensively through shear strains and crystallographic re-orientations associated with the growth of twins, little is known about the strengthening mechanisms associated with this deformation mode. A crystal plasticity based phase field model for twinning is employed in this work to study the strengthening mechanisms resulting from the interaction between twin growth and precipitates. The full-field simulations reveal in great detail the pinning and de-pinning of a twin boundary at individual precipitates, resulting in a maximum resistance to twin growth when the precipitate is partially embedded in the twin. Furthermore, statistically representative precipitate distributions are used to systematically investigate the influence of key microstructural parameters such as precipitate orientation, volume fraction, size, and aspect ratio on the resistance to twin growth. The results indicate that the effective critical resolved shear stress (CRSS) for twin growth increases linearly with precipitate volume fraction and aspect ratio. For a constant volume fraction of precipitates, reduction of the precipitate size below a critical level produces a strong increase in the CRSS due to the Orowan-like strengthening mechanism between the twin interface and precipitates. Above this level the CRSS is size independent. The results are quantitatively and qualitatively comparable with experimental measurements and predictions of mean-field strengthening models. Based on the results, guidelines for the design of high strength magnesium alloys are discussed.

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Section: Introductionmentioning

confidence: 99%

On the interaction of precipitates and tensile twins in magnesium alloys

et al. 2019

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“…Strength of the alloy is achieved through solid‐solution hardening and, in particular, through the precipitation hardening by various aging treatments . Y forms precipitates inside grains and along grain boundaries . Additionally, Y has a high solid solubility in Mg introducing the solid‐solution hardening .…”

Section: Introductionmentioning

confidence: 99%

“…9,10,51 Y forms precipitates inside grains and along grain boundaries. 50,52,53 Additionally, Y has a high solid solubility in Mg introducing the solid-solution hardening. 14,37,39 Precipitates contribute to strengthening the material are either globular or platelike shaped.…”

Section: Introductionmentioning

confidence: 99%

Low‐cycle fatigue behavior of rolled WE43‐T5 magnesium alloy

Ghorbanpour

McWilliams

Knežević

2019

Fatigue Fract Eng Mat Struct

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This paper describes the main results from an investigation into the strength and low‐cycle fatigue (LCF) behavior of a rolled plate of WE43 Mg alloy in its T5 condition at room temperature. The alloy was found to exhibit small tension/compression yield asymmetry and small anisotropy being stronger in transverse direction (TD) than in rolling direction (RD) along with some anisotropy in strain hardening. The LCF tests were conducted under strain‐controlled conditions with the strain amplitudes ranging from 0.6% to 1.4% without the mean strain component. While the stress amplitudes during the LCF were higher for tests along TD than RD, the LCF life was similar for both directions. As revealed by electron microscopy, the fractured surfaces under tension consisted mainly of microvoid coalescence with some transgranular facets, while those fractured in LCF showed a combination of intergranular fracture and transgranular facets with minor content of microvoid coalescence.

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“…The increase in CRSS of prismatic and <c+a> slip modes due to the plate shaped particles has recently been established by Wang et al (2016) Note that the core radius, r 0 , is assumed equal to the appropriate b in the above calculations. Choo (2014) is employed).…”

Section: Precipitation Strengtheningmentioning

confidence: 99%

“…Several researchers have focused on characterizing the precipitation sequence and the structure of the metastable precipitates (e.g., Antion et al, 2003). Moreover, quite a few studies have employed theoretical calculations based on Orowan bowing mechanism to calculate the effect of precipitate geometry on different slip modes (Nie, 2003;Wang et al, 2016). These calculations reveal that plate shaped precipitates lying on non-basal planes are effective in strengthening all slip modes.…”

Section: Introductionmentioning

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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Effect of precipitate shape and orientation on Orowan strengthening of non-basal slip modes in hexagonal crystals, application to magnesium alloys

Cited by 152 publications

References 21 publications

On the interaction of precipitates and tensile twins in magnesium alloys

On the interaction of precipitates and tensile twins in magnesium alloys

Low‐cycle fatigue behavior of rolled WE43‐T5 magnesium alloy

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

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