Influence of martensitic steel ultrafine-grained structure on diffusion processes at low-temperature ion nitriding

5th International Congress on Energy Fluxes and Radiation Effects 2016

Ramazanov, K.N.^1 ; Esipov, R.S.^1 ; Vardanyan, E.L.^1 ; Agzamov, R.D.^1

Ufa State Aviation Technical University, Department of Mechanical Engineering, 12 Karla Marksa Str., Ufa, Russia^1

关键词: Constant voltage mode;    Diffusion process;    Low temperatures;    Low-temperature modification;    Research results;    Severe plastic deformations;    Surface microhardness;    Ultrafine grained structure;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/830/1/012074/pdf
DOI  :  10.1088/1742-6596/830/1/012074

来源: IOP

【 摘 要 】

The paper presents research results on the influence of martensitic steel ultrafine-grained (UFG) structure on diffusion processes at low-temperature ion nitriding. UFG structure was obtained through severe plastic deformation by torsion (SPDT) of coarse-grained (CG) steel samples. Ion nitriding was performed under the constant voltage mode during 4 hours at a temperature of 420 °C. Optical microscope was used to study the microstructure of a sample. Thickness of a modified layer was defined according to measurements of microhardness by depth. The analysis of research results showed that UFG steel structure enhances effective intensification of diffusion processes by 1.7 times, which in its turn contributes to low-temperature modification of a surface. At the same time, surface microhardness of UFG steel after treatment amounted to 1,200 HV and 525 HV of CG steel correspondingly.