Exceptionally high spallation strength for a high-entropy alloy demonstrated by experiments and simulations

Thürmer, Daniel; Zhao, Shiteng; Deluigi, Orlando; Stan, Camelia; Alhafez, Iyad Alabd; Urbassek, Herbert M.; Meyers, Marc A.; Bringa, Eduardo M.; Gunkelmann, Nina

doi:10.1016/j.jallcom.2021.162567

Cited by 35 publications

(12 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Recent spallation studies of an fcc HEA alloy show a spall strength much higher than for any fcc metal [43]. Our results for a single crystal bcc HEA alloy would suggest a lower spall strength than for pure Ta.…”

Section: Discussioncontrasting

confidence: 48%

“…At high temperatures, the mechanical behavior of HEAs could be affected not only by changes in dislocation mobility due to temperature [80], but also due to the HEA composition [85]. Future studies could assess the influence of initial Recent spallation studies of an fcc HEA alloy show a spall strength much higher than for any fcc metal [43]. Our results for a single crystal bcc HEA alloy would suggest a lower spall strength than for pure Ta.…”

Section: Discussionmentioning

confidence: 73%

“…Experimental evidence suggests that HEAs are prone to ductile failure by void initiation, growth, and coalescence. Such a scenario is expected under a variety of loading conditions, including spallation [43]. To shed light into elusive aspects of void growth in HEAs under tensile stresses and high strain-rate conditions, we systematically explored the effect of a void immersed in a bcc HfNbTaZr HEA using molecular dynamics simulations.…”

Section: Discussionmentioning

confidence: 99%

“…In order to explore strain-rate effects, selected cases were run at a strain-rate of 10 8 s −1 . These strain rates are characteristic of shock spallation experiments [43], where the dissipation of local heating is severely impeded, as well as the expansion in the directions perpendicular to the shock direction, and the use of a NPT ensemble would lead to artificial results. Because of this reason, many previous studies of void growth [35,44] have used the NVE ensemble during loading, as it is done here.…”

Section: Samples and Simulation Protocolmentioning

confidence: 99%

See 3 more Smart Citations

Atomistic Simulations of Ductile Failure in a b.c.c. High-Entropy Alloy

Aquistapace

Vazquez

Chiarpotti

et al. 2022

High Entropy Alloys & Materials

Self Cite

View full text Add to dashboard Cite

Ductile failure is studied in a bcc HfNbTaZr High-Entropy Alloy (HEA) with a pre-existing void. Using molecular dynamics simulations of uniaxial tensile tests, we explore the effect of void radius on the elastic modulus and yield stress. The elastic modulus scales with porosity as in closed-cell foams. The critical stress for dislocation nucleation as a function of the void radius is very well described by a model designed after pure bcc metals, taking into account a larger core radius for the HEA. Twinning takes place as a complementary deformation mechanism, and some detwinning occurs at large strain. No solid-solid phase transitions are identified. The concurrent effects of element size mismatch and plasticity lead to significant lattice disorder. By comparing our HEA results to pure tantalum simulations, we show that the critical stress for dislocation nucleation and the resulting dislocation densities are much lower than for pure Ta, as expected from lower energy barriers due to chemical complexity.

show abstract

Section: Discussioncontrasting

confidence: 48%

Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Samples and Simulation Protocolmentioning

confidence: 99%

See 2 more Smart Citations

Atomistic Simulations of Ductile Failure in a b.c.c. High-Entropy Alloy

Aquistapace

Vazquez

Chiarpotti

et al. 2022

High Entropy Alloys & Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…Spall failure of HEAs under dynamic impact cannot be ignored for defense applications. Hawkins et al [28] conducted a series of shock loading experiments with projectile speed 300 m s -1 on FeCrMnNi HEA. It concludes that the compressive strength is not high enough although the spall strength is relatively high ~1.9 GPa.…”

Section: Investigation and Application Of The Heas At High Strain Ratesmentioning

confidence: 99%

High Entropy Alloys for Extreme Load-Bearing Applications

Zhao¹,

Li²

2022

MatLab

Self Cite

View full text Add to dashboard Cite

High entropy alloys (HEAs) have emerged as a new class of materials that can exhibit superior mechanical properties to the conventional alloy systems. Therefore, they are promising candidates as the next generation structural materials. As the studies into the HEAs deepen, the original proposal of equal concentration of each element while remaining a single phased structure has been expanded and new opportunities start to emerge. Here we briefly discuss several future directions for HEAs which include fundamental questions such as chemical short-range order and synergistic strengthening mechanisms, as well as HEA’s potential applications under extreme conditions such as high-temperature and cryogenic load-bearing, impact protection and kinetic penetrator.

show abstract