Research on Surface Nanocrystallization of Surfacing Layer by Pre-loading Rolling Technology

Abstract

The surface microstructure of the surfacing layer was optimized by refining the coarse grains to nanocrystalline by means of pre-loading rolling treatment(PLRT). By using of field emission scanning electron microscope and transmission electron microscopy observations, the microstructural features in the treated surfacing layer were characterized, and processing parameters were optimized. The experimental results show that the obvious plastic deformation layer is formed on the surfacing layer after rolling processing. A uniform refining nanostructured surface layer up to 10μm is fabricated on the surfacing layer. The grain size of the nanocrystalline surface layer is about 10nm. The roughness of PLRTed sample is reduced. The surface residual stress of PLRTed sample change from tensile stress of untreated sample to compressive stress. Analysis shows that the coarse grain of surfacing layer can be effectively refined into nanocrystalline by means of PLRT, and surface physical condition is optimized.

Friction and wear properties of a sulphurized layer formed by low-temperature ion sulphurization on a surface nanocrystallized layer

“…The rolling process was repeated four times. The preload rolling system and its operational principles are explained in detail elsewhere [12,18]. A high-frequency pulsed plasma diffusion system was used to perform LTIS on the samples.…”