Anisotropy dependence of chip formation and plastic deformation in Fe-25Cr-20Ni austenitic stainless steel during micro-scratching

The wear characteristics of the tribological pair and the mechanisms of material removal are significantly influenced by the plastic deformation of the contact surface during the tribological process of metallic materials. Chip formation is recognized as one of the primary mechanisms contributing to material loss during the wear process. However, the underlying mechanisms governing chip formation remain incompletely elucidated. This paper employs micro-scratch testing to investigate the wear behavior of the {001}, {101}, and {111} grains in austenitic stainless steel under varying scratch directions and applied loads. The transition from initial indentation contact to plowing and subsequent chip formation is systematically examined, revealing the influence of crystallographic orientation and scratch direction on chip formation mechanisms. Our results demonstrate that the chip formation and plastic deformation exhibit substantial dependence on crystallographic orientation and scratch direction, which are closely associated with the activation of specific slip systems within the grains. The depth profile within the worn track and the surface topography surrounding it have a major impact on the frictional response and chip formation process. A critical depth for chip formation is identified under specific loading conditions, below which chip formation is more likely to occur. This research provides valuable insights into the micro-scale tribological behavior of face-centered cubic metallic materials, offering a theoretical foundation for optimizing material properties, enhancing wear resistance, and prolonging service life in engineering applications.