Dynamic tensile failure of rolled magnesium: Simulations and experiments quantifying the role of texture and second-phase particles

Lloyd, Jeffrey T.; Matejunas, Andrew; Becker, Richard; Walter, Tim; Priddy, Matthew W.; Kimberley, Jamie

doi:10.1016/j.ijplas.2018.11.002

Cited by 29 publications

(3 citation statements)

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“…In the case of low rate loading (less than 10 0 s −1 ), the failure of magnesium and its alloys typically occurs as brittle fracture in shear modes [1,2]. Dynamic failure (more than 10 3 s −1 ) of Mg and Mg alloys tends to depend more on the texture and the presence of large second phase particles as failure nucleation sites [3]. Under dynamic conditions experienced by protection materials undergoing ballistic impact, magnesium has shown a relatively low resistance to cavitation-driven spall failure, however the advantageous specific strength continues to draw interest in impact applications where Mg has a tremendous weight savings potential for vehicle and personnel armor [4].…”

Section: Introductionmentioning

confidence: 99%

A Brief Review of Spall Failure in Pure and Alloyed Magnesium

Mallick

Williams

Wilkerson

2020

J. dynamic behavior mater.

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The ratio of the yield strength to the density (specific strength) of magnesium and its alloys is relatively high, but cavitationdriven spall failure of these materials occurs at low threshold stresses and strains. The low failure threshold suggests a general susceptibility to catastrophic failure under tension at high rates of deformation. Higher material strength likely prevents such failure, but processing methods to achieve these strengths can introduce potential failure nucleation sites that can make failure more likely-the interplay between matrix strength and nucleation sites remains largely unknown. Here we examine the literature regarding experimental observation of spall failure of pure and alloyed magnesium with a particular emphasis on the trends between grain size and strain rate with respect to the spall failure strength. We then apply an analytical dynamic cavitation model to better understand the role of second phase particles in spall failure. We find that the conventional polycrystalline alloys with micron sized grains have microstructures containing second phase particles that act as failure nucleation sites, diminishing the potential to design against low failure threshold stresses. Additionally, nanocrystalline grained magnesium remains largely unexplored and may potentially offer an avenue for greater dynamic strength.

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Section: Introductionmentioning

confidence: 99%

A Brief Review of Spall Failure in Pure and Alloyed Magnesium

Mallick

Williams

Wilkerson

2020

J. dynamic behavior mater.

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“…The Kinetic equation of aggregation and growth of the second phase particles can be used to determine the phase boundary energy between the matrix phase and the second phase particles [ 35 ]. The corresponding mathematical formulation is expressed in Equation (9) below:

…”

Section: Molecular Dynamic Modelingmentioning

confidence: 99%

Mechanical Properties of the Interfacial Bond between Asphalt-Binder and Aggregates under Different Aging Conditions

et al. 2021

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Aging has a detrimental impact on the interfacial interaction and bonding between asphalt-binder and aggregates, which influence ultimately on the performance of asphalt mixtures and pavements. Evaluation of the mechanical properties of the interface between the asphalt-binder and aggregates has thus become a hot research topic, particularly as a function of aging. In this study, the interfacial tensile strength, compressive strength, elastic modulus, and interfacial recovery energy were measured and quantified using molecular dynamic simulation. Whilst the free volume of the asphalt mixtures exhibited sensitivity to aging, the interfacial tensile strength decreased with an increase in the degree of aging. In general, the mechanical properties of the asphalt-binder-aggregate interface were found to be significantly dependent on the aggregate type. Furthermore, the study results indicated that interfacial recovery energy is a key characteristic property for characterizing the interfacial adhesive force within asphalt mixtures. Overall, the study of mechanical properties of the asphalt-binder and aggregate interface, as presented in this paper, contributes to quantifying the adhesive properties and improving the performance of asphalt mixtures.

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“…Indeed, there exists a good deal of variability in the reports on grain size effects in same Mg alloys subjected to different thermo-mechanical processes, which makes it difficult to reliably predict their macroscopic responses [7,33]. The situation may become even more complicated with different rates and states of loading [34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%