Roller burnishing of Ti6Al4V under different cooling/lubrication conditions and tool design: effects on surface integrity

The paper presents a deep experimental study on surface modifications induced by roller burnishing process of Ti6Al4V titanium alloy. The experimental campaign has been performed based on a design of experiments at varying lubrication/cooling strategies, roller geometry, coating, and burnishing speed. The overall surface integrity has been analyzed in terms of surface roughness, micro hardness, topography, microstructural changes, and tribological performance. The results allowed to better define the relationships within burnishing process parameters and the surface quality of the final component. In particular, the obtained evidences show that cryogenic cooling conditions and coating tools significantly improve the hardness of the final component while the MQL lubrication leads to superior surface roughness. Overall, the process always improves the wear resistance of the components with optimal results when cryogenic cooling and coated tools are employed. Thus, the outcomes of the extensive experimental campaign allow to define a combination of process parameters leading to improved Ti6Al4V surface quality.