Influence of nanoparticles’ size on Inconel 718 machining induced residual stresses

One of the main problems in the cutting of Inconel 718 is high machining force and temperatures as well as machining-induced residual stresses (σres.) which are often tensile. One of the approaches in resolving these issues relies on the use of cutting fluids. Today, nanofluids (NFs) are increasingly employed as the cutting fluid in various machining procedures to improve the thermal properties, and anti-wear and anti-friction features of the lubricant fluid. Researches focused on the thermo-tribological characteristics of NFs indicated that nanoparticles (NPs) size and material, base fluid (BF) type and content of NPs in BF can affect the magnitude of machining forces and temperatures in the machining processes and thus σres. The current research explores the impact of the cutting speed and NPs size and content in BF on σres of Inconel 718. Based on the results, with the application of TiO2 nanofluid, the mean value of σres got more compressive by 15.73% compared to machining with conventional lubricant. However, by enhancing the NPs size from 10 to 50 nm, the amount of decrement in residual stresses declined from 20.03 to 11.44%.