Study on the Wear Performance of 20CrMnTi Gear Steel with Different Penetration Gradient Positions.

This study investigates the wear performance of 20CrMnTi steel, a commonly used material for spiral bevel gears, after heat treatment, with a focus on the microstructural evolution and wear behavior in both the surface and gradient direction of the carburized layer. The results show that the microstructure composition in the gradient direction of the carburized layer gradually transitions from martensite and residual austenite to a martensite-bainite mixed structure, and eventually transforms to fully bainitic in the matrix. With the extension of carburizing time, both the effective carburized layer depth and the hardened layer depth significantly increase.

Electron Beam-Assisted Au Nanocrystal Shear and Rotation.

Understanding metastable structural transitions under beam irradiation is essential for the phase engineering of nanomaterials. However, in situ studies of beam-induced structural transitions remain challenging. This work uses an electron beam in aberration-corrected high-angle annular dark-field scanning transmission electron microscopy to irradiate Au nanocrystals at room temperature.