Characterization of Surface Modification of 347 Stainless Steel upon Shot Peening

• Published in: Scanning Vol. 2017; no. 2017; pp. 1 - 4
• Main Authors: Shin, Keesam, Cao, Pengjun, Sun, Jianchun, Chen, Dengming, Guo, Donglin, Shao, Bin, Li, Chunhong, Zheng, Qiang, Li, Kejian, Dong, Jiling
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01-01-2017; Hindawi; Hindawi Limited
• Subjects: Austenite; Austenitic stainless steels; Corrosion resistance; Ductility; Electron backscatter diffraction; Electrons; Failure analysis; Grain refinement; Grain size; Martensite; Martensitic transformations; Materials fatigue; Mechanical properties; Metal fatigue; Microstructure; Phase transitions; Plastic deformation; Scanning electron microscopy; Science; Shot peening; Stainless steel; Surface treatment; X-ray diffraction
• ISSN: 0161-0457; 1932-8745
• DOI: 10.1155/2017/2189614

Plastic deformations, such as those obtained by shot peening on specimen surface, are an efficient way to improve the mechanical behavior of metals. Generally, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) are commonly used to observe the complex microstructural evolutions, such as grain refinement and phase transformation, induced by the surface treatment. In this work, the microstructure of 347 stainless steel, after ultrasonic shot peening (USP) treatments, was investigated. SEM, EBSD, transmission electron microscopy, and X-ray diffraction were used to observe the microstructural evolutions, such as grain refinement and phase transformation. Deformation depth after the USP treatment was about 200 μm. Grain size on the treated surface layer was about 100 nm, with two phases: austenite and α′-martensite. The percentages of the austenite and α′-martensite phases were 54% and 46%, respectively, which constitute an exact expression of the degree of plastic deformation on austenitic stainless steel.