Assessment on the wear failure of additively manufactured stainless steel 316L with different scan pattern in simulated body fluid condition

Abstract

Because of higher contact area, the additively manufactured SS 316L (AM built 316L) generates a high frictional heat and wear in the lubricated sliding condition. So to counteract this, different scan patterns like stripe, contour and porous-chessboard were developed for AM built 316L to reduce the contact area. Importantly, the variation in scan patterns could induce different wear mechanisms when two surfaces slide against each other. Therefore, it is essential to analyse the wear failures for the different scan patterns in simulated body fluid (SBF) conditions, which was not carried out previously. In the present study, the simulated body fluid (SBF) conditions are designed to mimic the chemical and physical properties of body fluids and also, the article correlates how the tribological behaviour of AM-built 316L varies in the SBF condition. Furthermore, the porosity, elemental composition, surface roughness, density, phase structure, residual stress, hardness, friction, and wear properties of AM built 316L samples has been characterized. X-ray diffractometer (XRD) analysis confirmed the presence of high intensity γ-Fe (111) peaks for the porous-chessboard pattern, because of high dislocation density. Compressive residual stress has been reported for all scan patterns due to the difference in the thermal expansion and contraction between the built layers. Novel cross linked porous-chessboard pattern has a higher wear resistance with low COF compared to the other scan pattern. Furthermore, the exhibition of different wear mechanisms like abrasive and adhesive wear, breaking of lubrication film, patches, and fatigue regions for the different scan patterns were detailed in this study.