On the behaviour of the magnesium alloy, AZ61 to one-dimensional shock loading

Millett, J. C. F.; Stirk, S. M.; Bourne, N. K.; Gray, George T.

doi:10.1016/j.actamat.2010.06.042

Cited by 37 publications

(18 citation statements)

References 32 publications

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“…Given the vast number of GB types and grain characteristics, it is highly desirable to investigate some elemental processes, such as columnar crystals or bicrystals, so we can grain certain specific insights without being overwhelmed by the complexities of abundant random GBs. In addition, due to the highly transient nature of shock events, it is extremely challenging to acquire the real-time measurements of microstructure responses [8][9][10][11][12][13][14][15][16][17][18]. In contrast, MD simulations are capable of supplying real-time data for understanding dynamic materials physics/mechanics of a wide range of materials/microstructures at atomic scales, including single crystals, nanocrystalline metals, glasses, polymers, and composites [19][20][21][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

“…[8,9]. Shock experiments [8][9][10][11][12][13][14][15][16][17][18] have been routinely performed on polycrystalline solids along with very limited molecular dynamic (MD) simulations in past few decades [19][20][21][22][23][24][25][26][27]. Given the vast number of GB types and grain characteristics, it is highly desirable to investigate some elemental processes, such as columnar crystals or bicrystals, so we can grain certain specific insights without being overwhelmed by the complexities of abundant random GBs.…”

Section: Introductionmentioning

confidence: 99%

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Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

Han

Luo

et al. 2012

Phys. Rev. B

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We perform molecular dynamics simulations of Cu bicrystals with two important GBs, Σ3 coherent twin boundaries (CTB) and symmetric incoherent twin boundaries (SITB), under planar shock wave loading. It is revealed that the shock response (deformation and spallation) of the Cu bicrystals strongly depends on the GB characteristics. At the shock compression stage, elastic shock wave can readily trigger GB plasticity at SITB but not at CTB. The SITB can induce considerable wave attenuation such as the elastic precursor decay via activating GB dislocations. For example, our simulations of a Cu multilayer structure with 53 SITBs (~1.5 µm thick) demonstrate a ~80% elastic shock decay. At the tension stage, spallation tends to occur at CTB but not at SITB due to the high mobility of SITB. The SITB region transforms into a threefold twin via a sequential partial dislocation slip mechanism, while CTB preserves its integrity before spallation. In addition, deformation twinning is a mechanism for inducing surface step during shock tension stage. The drastically different shock response of CTB and SITB could in principle be exploited for, or benefit, interface engineering and materials design.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

Han

Luo

et al. 2012

Phys. Rev. B

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“…3. Evidence of precursor decay has been seen in AZ61 [3], however, for the T5 alloy this was not the case. This behavior is tentatively attributed to the nature of the precipitation-hardening heat treatment that hinders dislocation nucleation and mobility (the principal mechanism by which precursor decay would be expected to occur).…”

Section: Hugoniot Elastic Limitmentioning

confidence: 80%

“…The gauge results revealed that the T5 alloy had a HEL of 0.38 ± 0.02 GPa, considerably higher than that of AZ61 [3]. However unlike AZ61, where tentative evidence of precursor decay was found with increasing target thickness, the T5-alloy's HEL did not decay.…”

Section: Hugoniot Elastic Limitmentioning

confidence: 80%

On the shock response of the magnesium alloy elektron 675

Hazell

Appleby-Thomas

Wielewski

et al. 2012

AIP Conference Proceedings

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The resistance to deformation and facture of magnesium ma2-1 under shock-wave loading at 293 k and 823 k of the temperature AIP Conference Proceedings 1426, 935 (2012) Abstract. Alloying elements such as aluminum, zinc or rare-earths allow precipitation hardening of magnesium (Mg). The low densities of such strengthened Mg alloys have led to their adoption as aerospace materials and (more recently) they are being considered as armor materials. Consequently, understanding their response to high strain-rate loading is becoming increasingly important. Here, the plate-impact technique was employed to measure longitudinal stress evolution in armor-grade wrought Mg-alloy Elektron 675 under 1D shock loading. The spall behavior was interrogated using a Heterodyne velocimeter (Het-v) system, with an estimate made of the material's Hugoniot elastic limit for both aged and un-aged materials.

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“…However, from equation 2, it can be seen that shear strength can also be measured using suitably orientated manganin stress gauges. This methodology has been used by ourselves and others on a variety of materials including metals and alloys [10][11][12], ceramics and silicate glasses [13][14][15] and polymers [16][17][18]. It can be seen that this is an invasive procedure, in that a manganin stress gauge must be introduced into a sectioned target assembly, and as such, it has been suggested that in doing so, the lateral stress recorded by the gauge is more a function of the layer of adhesive it sits in due to target assembly [19].…”

Section: Introductionmentioning

confidence: 99%

Shear strength measurements in a shock loaded commercial silastomer

Millett¹,

Whiteman²,

Stirk³

et al. 2011

J. Phys. D: Appl. Phys.

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The shock-induced shear strength of a commercial silastomer, trade name Sylgard 184™, has been determined using laterally mounted manganin stress gauges. Shear strength has been observed to increase with increasing shock amplitude, in common with many other materials. Shear strength has also been observed to increase slightly behind the shock front as well. It is believed that a combination of polymer chain entanglement and cross linking between chains is responsible. Finally, a ramp on the leading edge of the lower amplitude stress traces has been observed. It has been suggested that this is due to shock-induced collapse of free space between the polymer chains. Similar explanations have been used to explain the apparent non-linearity of the shock velocity with particle velocity at low shock amplitudes.

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On the behaviour of the magnesium alloy, AZ61 to one-dimensional shock loading

Cited by 37 publications

References 32 publications

Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

Deformation and spallation of shocked Cu bicrystals withΣ3 coherent and symmetric incoherent twin boundaries

On the shock response of the magnesium alloy elektron 675

Shear strength measurements in a shock loaded commercial silastomer

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