The compressive and tensile behaviors in a Ti nanopillar with a biphasic hexagonal close-packed (HCP) /face-centered cubic (FCC) phase boundary are theoretically researched using classic molecular dynamic simulation. The results indicate that the HCP/FCC interface and free surface of the nanopillar are the sources of dislocation nucleation. The plastic deformation is mainly concentrated in the metastable FCC phase of the biphasic nanopillar. Under compressive loading, a reverse phase transformation of FCC to the HCP phase is induced by the dislocation glide of multiple Shockley partial dislocations 1 6 <121> under compressive loading. However, for tensile loading a large number of Lomer-Cottrell sessile dislocations and stacking fault nets are formed when the partial dislocations react, which leads to an increase in stress. The formation mechanism of a Lomer-Cottrell sessile dislocation is also studied in detail. Shockley partial dislocations are the dominant mode of plastic deformation behaviors in the metastable FCC phase of the biphasic nanopillar.
Based on first‐principles with the generalized gradient approximation (GGA) of the Perdew–Burke–Ernzerhof (PBE) form, the authors carry out systematic investigations regarding the electronic structures and optical properties of zinc‐blende (ZB) ZnS doped with six types of transition metals. The Cd‐doped system has greater structural stability with a lower formation energy of 0.526 eV compared to other systems. Additionally, the band structures of systems are employed to show the superior semiconductor capacity of Mo‐ and Pt‐doped systems with decreased band gaps (EG) of 0.978 eV and 0.843 eV, which are smaller than those of the pure system and others. Moreover, charge difference density maps show that the covalent properties of MoS and PtS bonds are enhanced by exposing the electron‐deficient region. Meantime, optical properties, including absorption and reflectivity spectra, dielectric constant, and loss function, are introduced to reveal that the absorption spectra curves reach the lowest absorption peak of 2.375 × 105 cm−1 at 7.227 eV for the Mo‐doped system, in which the system exhibits a relatively negative reflectivity spectrum and dielectric loss that is expected in the solar cell industry, predicting its broad scope of application prospects in the photoelectric and microelectronic device fields.
The mechanism of plastic deformation under tensile and compressive loading of hexagonal close-packed (HCP)/face-centered cubic (FCC) biphasic titanium (Ti) nanopillars at different temperatures (70 K, 150 K, 300 K and 400 K) and different FCC phase sizes (2 nm, 4 nm, 6 nm and 8 nm) was investigated by molecular dynamics (MD). The plastic deformation is mainly concentrated in the FCC phase during compression loading. The HCP/FCC interface is the main source of [Formula: see text] Shockley partial dislocations. As the temperature increases, the dislocation nucleation rate increases and the surface dislocation source is activated. During tensile loading, it is more likely that the Shockley partial dislocations react with each other in the FCC phase to form Lomer–Cottrell sessile dislocations and stacking fault (SF) nets. When the temperature is reduced to 70 K, tensile twins are formed at the phase interface. The plastic deformation is dominated by twins and [Formula: see text] dislocation slip occurs in the HCP phase. The effect of the FCC phase size on the plastic deformation mechanism of the nanopillar is strong. The FCC phase is transformed into the HCP phase when the FCC phase size in the nanopillar is reduced to 4 nm under compressive loading. However, twin deformation occurs at the HCP/FCC interface when the FCC phase size is reduced to 2 nm under tensile loading.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.