Austenitic stainless steels have been widely used in engineering applications due to their unique and outstanding properties, such as their excellent corrosion resistance. However, the mechanical properties of these steels are affected by the nucleation and formation of deformation-induced martensite (as occur in TRIP steels).
In this study, we investigate the wear behaviour and martensitic transformation evolution that take place in different stainless steel grades (i.e. Cr-Ni austenitic stainless steel and ferritic-austenitic super duplex) and in a TRIP steel by means of scratching tests. Single-stroke scratches were performed on a clean air environment at room temperature and without lubrication using an instrumented nanoindenter with normal force control and equipped with a spherical diamond tip. All the experiments were conducted with normal contact forces between 5 and 80 mN and sliding velocities between 1 and 100 µm/s.
The microstructural characterization and texture resulting from the martensitic transformation were analyzed by scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD). We quantify the amount and spread of martensite as a function of the counter body radius and as a function of the normal force.
SEM analysis shows significant wear damage and also that plasticity is dominant in the range of forces applied. EBSD patterns reveals that the initial crystallographic orientation of the host grain has a considerable effect on the texture and phase transformation.