Analysis of surface layer characteristics after machining of a Ni-based superalloy

The current study intends to investigate the role of advanced coated tool consisting of TiN/TiAlN multilayer coating as well as cutting environment during the machining of Incoloy 825. Condition of machining (roughing and finishing) and cutting tools (new and worn) have also been evaluated. The coated tool was utilised under environment friendly dry machining, while uncoated tools were used under flood cooling and minimum quantity lubrication (MQL). Cutting temperature and various characteristics of surface integrity including surface roughness, surface morphology, formation of white layer, hardness depth profile and residual stress have been compared under different conditions of machining. Although maximum temperature was recorded with the PVD coated tool under dry environment, the same tool resulted in overall improvement in surface integrity compared to the uncoated tools used for wet machining. According to the general trend, flood cooling was more beneficial than MQL when overall machined surface integrity of Ni-based superalloys was considered.