Publications by authors named "Y K Vohra"
We report on the high-resolution imaging and molecular dynamics simulations of a 3D-printed eutectic high-entropy alloy (EHEA) NiCoFeCrAlW consisting of nanolamellar BCC and FCC phases. The direct lattice imaging of 3D-printed samples shows the Kurdjumov-Sachs (K-S) orientation relation {111} FCC parallel to {110} BCC planes in the dual-phase lamellae. Unlike traditional iron and steels, this alloy shows an irreversible BCC-to-FCC phase transformation under high pressures.
View Article and Find Full Text PDFFirst-principles calculation of Hubbardfor Terbium metal under high pressure.
J Phys Condens Matter
July 2024
Article Synopsis
- The study uses density functional theory (DFT) and linear response methods to calculate the on-site Hubbard interaction of Terbium (Tb) metal under pressures up to 65 GPa.
- It employs a DFT+U method to analyze the magnetic properties of different high-pressure phases of Tb, finding that the lowest-energy magnetic states match experimental observations.
- The research highlights how incorporating the Hubbard interaction enhances modeling of rare-earth materials and offers insights for further quantum many-body studies under extreme pressures.
A boron-rich boron-carbide material (BC) was synthesized by spark plasma sintering of a ball-milled mixture of high-purity boron powder and graphitic carbon at a pressure of 7 MPa and a temperature of 1930 °C. This high-pressure, high-temperature synthesized material was recovered and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Vickers hardness measurements, and thermal oxidation studies. The X-ray diffraction studies revealed a single-phase rhombohedral structure (space group R-3m) with lattice parameters in hexagonal representation as = 5.
View Article and Find Full Text PDFArticle Synopsis
- Metal oxide thermal reduction using microwave-induced plasma was employed to create high entropy borides (HEBs), utilizing an argon-rich plasma for efficient energy transfer.
- Two synthesis methods were compared: boro/carbothermal reduction (with carbon) and borothermal reduction (without carbon), revealing distinct differences in microstructural and mechanical properties.
- The HEBs produced with carbon showed greater hardness (38 ± 4 GPa) and density, as well as reduced porosity, compared to those made without carbon (28 ± 3 GPa).