A research on the microstructure evolution of austenite stainless steel by surface mechanical attrition treatment

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 617; pp. 127 - 138
• Main Authors: Liu, S., Gao, S.Y., Zhou, Y.F., Xing, X.L., Hou, X.R., Yang, Y.L., Yang, Q.X.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 03.11.2014; Elsevier
• Subjects: Annealing; Applied sciences; Attrition; Austenite; Austenitic stainless steels; Condensed matter: electronic structure, electrical, magnetic, and optical properties; EBSD; Electron and ion emission by liquids and solids; impact phenomena; Electron back scatter diffraction; Electron microscopy; Evolution; Exact sciences and technology; Field emission, ionization, evaporation, and desorption; Grain boundaries; Grain refinement; Grains; Hardness; Heat treatment; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Physics; Production techniques; Scanning electron microscopy; Surface treatment; X-ray diffraction; Grain boundaries; X-ray diffraction; Electron microscopy; Grain refinement; EBSD; Austenite; High strain; Confocal microscopy; Field emission; Plastic deformation; Crystal defect; Dislocation; Grain boundary; Scanning microscope; Mechanical treatment; X ray diffractometer; Scanning electron microscopy; Annealing; Mechanical properties; Mechanical twin; Hardness; X ray diffraction; Electron field emission; Surface treatment; Attrition mill; Laser microscope; Transmission electron microscopy; Stainless steel; Microstructure
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2014.08.049

Severe plastic deformation (SPD) was performed on AISI304 stainless steel by surface mechanical attrition treatment (SMAT). The microstructure evolution of the specimens along the depth direction were examined by transmission electron microscope (TEM) and electron backscattered diffraction (EBSD) associated with field emission scanning electron microscope (FESEM). The results show that the specimens by SMAT can be divided into three regions. Region I is the untreated one, where a large number of annealing twins exist. Region II is the small plastic-deformed one, where the grains are deformed by dislocation slipping. Region III is the severe plastic-deformed one, where the grains are deformed by mechanical twinning. The hardness of the untreated and the treated specimens were determined, which shows that the hardness of the untreated specimen (including region I) is about 250HV, while the hardness is uniformly increased from region II to region III, and the largest value appears on the surface. The untreated and the 600N-treated specimens were determined and observed by X-ray diffractometer (XRD) and confocal laser scanning microscope (CLSM), which shows that the SMAT treated specimen exhibits a layer of ultra-fined γ-Fe grains on the treated surface.