To study the microstructural evolution in high-strain-rate shear deformation of Ti-5Al-5Mo-5V-1Cr-1Fe (Ti-55511) alloy, a series of forced shear tests of hat-shaped specimens have been conducted using a split Hopkinson pressure bar combined with the "strain-frozen" technique. A localized shear band is induced in Ti-55511 alloy in these tests. The experimental results demonstrate that the flow stress in hat-shaped specimens remains constant (about 600 MPa) and is independent of punching depth. The width of the adiabatic shear band increases with increasing punching depth and tends to saturate at 30 μm, and the estimation of the adiabatic shear band (ASB) width in hat-shaped (HS) specimens has been modified. Relying on the experimental results, thermal softening has a minor effect on the onset of the adiabatic shear band and dynamic recrystallization formation, and the nucleation mechanism for dynamic recrystallization is strain-induced boundary migration and subgrain rotation and coalescence. In addition, we suggest the concept of adhesive fracture as the dynamic failure mechanism for Ti-55511 alloy.
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http://dx.doi.org/10.3390/ma11050839 | DOI Listing |
Aust Vet J
January 2025
Veterinary Referral Hospital, Dandenong, Victoria, Australia.
A 4-year-old Siberian Husky was referred for bilateral hock trauma after being involved in a road traffic accident. The dog sustained a grade 3 shearing injury to the medial right hock with tibiotarsal subluxation, which was managed with a transarticular frame. The left hock sustained a rare open longitudinal split fracture of the lateral malleolus, resulting in lateral tarsocrural instability.
View Article and Find Full Text PDFThe potential application of materials referred to as perovskite hydrides in hydrogen storage - a crucial element of renewable energy systems - has sparked a great deal of interest. We use density functional theory (DFT) to investigate the structural, formation energy, hydrogen storage, electronics, thermoelectric and elastic properties of NaXH (X = Be, Mg, Ca, and Sr) hydrides. The band gap is calculated using WC-GGA and WC-GGA+mBJ potentials.
View Article and Find Full Text PDFScience
December 2024
Department of Electrical and Computer Engineering, National University of Singapore, Kent Ridge, Singapore, Republic of Singapore.
The structural periodicity in photonic crystals guarantees the crystal's effective energy band structure, which is the fundamental cornerstone of topological and moiré physics. However, the shear modulus in most fluids is close to zero, which makes it challenging for fluids to maintain spatial periodicity akin to photonic crystals. We realized periodic vortices in hydrodynamic metamaterials and created a bilayer moiré superlattice by stacking and twisting two such vortex fluids.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Department of Mechanical Engineering, Howard University, Washington, DC 20059, USA.
This study examined the effects of heat treatment on the microstructure and dynamic deformation characteristics of AA2519 aluminum alloy in T4, T6, and T8 tempers under high strain rates of 1000-4000 s. A Split Hopkinson pressure bar (SHPB) was utilized to characterize the mechanical response, and microstructural analysis was performed to examine the material's microstructure. The findings indicated varied deformation across all three temper conditions.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
College of Science, Nanjing University of Posts and Telecommunications, Nanjing 210046, China.
Inspired by the recently reported novel two-dimensional material BCP, we performed one-dimensional shearing along the zigzag direction to obtain four BCP nanoribbons with various edge atom combinations. An asymmetric hydrogen passivation scheme was employed to modulate the electronic properties and successfully open the band gap, especially the 2H-1H passivation with dihydrogenation and monohydrogenation at the top and bottom edges, respectively, achieving bipolar magnetic semiconductors with edge P-atoms contributing to the main magnetism. Furthermore, three crucial spin-polarized transmission spectra yielded a significant spin-dependent Seebeck effect (SDSE), displaying superior thermoelectric conversion capabilities by generating pure spin currents.
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