Evolution of liquid phase during homogenous non-equilibrium melting of Ta at superheating temperature.

Homogenous melting at superheating temperature is commonly described by classical nucleation theory (CNT), but the atomic mechanism of the formation and development of critical liquid nuclei is still unclear. Molecular dynamics simulations were conducted to analyze the melting process of Ta. It is found that the process of subcritical liquid clusters evolving into critical liquid nucleus occupies most of the melting time, and merging between neighboring liquid clusters is the main path for subcritical liquid clusters to grow in size.

Observing and Modeling the Wear Process of Heterogeneous Interface.

Understanding and controlling the wear process of heterogeneous interfaces between soft and hard phases is crucial for designing and fabricating materials, such as improving the wear resistance of particle reinforced metal matrix composites and the accuracy and efficiency of chemical mechanical polishing. However, the wear process can be hardly observed, as interfaces are buried under the surface. Here, we proposed a nanowear test method by combining focused ion beam cutting to expose interfaces, atomic force microscopy to rub against interfaces, and scanning electron microscope to characterize the interface damage.

Bipolar charge transfer induced by water: experimental and first-principles studies.

The mechanism underlying bipolar charge distribution in the context of triboelectrification remains ambiguous. Furthermore, water can either promote or inhibit triboelectrification. It was determined through experimental and first-principles calculations that water can also reverse the polarity of transferred charges and cause a bipolar charge transfer.

Graded Microstructure and Mechanical Performance of Ti/N-Implanted M50 Steel with Polyenergy.

M50 bearing steels were alternately implanted with Ti⁺ and N⁺ ions using solid and gas ion sources of implantation system, respectively. N-implantation was carried out at an energy of about 80 keV and a fluence of 2 × 10 ions/cm², and Ti-implantation at an energy of about 40-90 keV and a fluence of 2 × 10 ions/cm². The microstructures of modification layers were analyzed by grazing-incidence X-ray diffraction, auger electron spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy.

Laser etching of groove structures with micro-optical fiber-enhanced irradiation.

A microfiber is used as a laser-focusing unit to fabricate a groove structure on TiAlSiN surfaces. After one laser pulse etching, a groove with the minimum width of 265 nm is manufactured at the area. This technique of microfabricating the groove in microscale is studied.