Nanoscale surface modification of AISI 316L stainless steel by severe shot peening. (15th July 2016)

• Record Type: Journal Article
• Authors: Bagherifard, Sara; Slawik, Sebastian; Fernández-Pariente, Inés; Pauly, Christoph; Mücklich, Frank; Guagliano, Mario
• Is Part Of: Materials & design. Volume 102(2016)
• Page Start: 68
• Page End: 77
• Publication Date: 2016-07-15
• Subjects: Severe shot peening -- Surface grain refinement -- Stainless steel 316L -- Biomedical implants -- Strain induced phase transformation; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.03.162
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Surface nanocrystallization is gaining increased attention due to its high potential of enhancing mechanical functionality and modulating material's interaction with the surrounding environment. Among mechanical approaches, severe shot peening has recently shown to be a very promising technique for surface grain refinement, considering its efficiency, eco-friendliness, relative low cost and minimum geometrical restrictions. This study evaluates the effect of severe shot peening on microstructural and mechanical properties of 316L stainless steel, which is widely used in biomedical, food preparation, structural and marine applications. 316 L samples, shot peened with different peening parameters, were studied in terms of morphological and structural features, defect density, grain size, phase transformation, surface topography, surface wettability, residual stresses and microhardness. The results indicated that severe shot peening induced near surface grain refinement to nano and sub-micron range and transformed the austenite phase into strain-induced α'- martensite in a layered deformation band structure. Severe shot peening also induced compressive residual stresses and work hardening in the top surface layer. Surface roughness and surface wettability, both of which favorably contribute to modulating the interaction of material with biological environment, were also notably enhanced by severe shot peening. Graphical abstract: Highlights: Severe shot peening induced gradient grain refinement from surface to the core. Austenite phase transformed into αʹ-martensite in the form of a layered structure. Martensite grains showed preferred orientation parallel to peening direction.