# Influence of Cutting Parameters and MQL on Surface Finish and Work Hardening of Inconel 617
## 2 Related Works  
Research in the field of manufacturing has been conducted extensively on the sister alloy, Inconel 718, which provides a basis to expand research on Inconel 617. One such work is performed by [PERSON] and [PERSON] on the influence of varying cutting parameters on the work hardening of Inconel 718 [8]. From their work, it was found that the cutting speed had a high impact on work hardening, with the degree of hardening increasing with higher cutting speeds, but the depth of work hardening conversely decreasing. Measurements were limited by the use of a micro-indenter to gather hardness profiles, which limited the scale at which the measurements could be performed. It was recommended by the authors to measure work hardening using a nano-indenter in future tests. [PERSON] and [PERSON] investigated the influence of high-speed MQL finish-turning on Inconel 718 [9]. This work investigated three tool coatings that were used to machine Inconel 718 under MQL. The authors found that the air pressure provided in MQL deposition had an impact on tool life, with higher air pressures causing a decrease in tool life, the inverse of their results when machining carbon steel [10]. From this, it is seen that the effectiveness of MQL is material-dependent and must be investigated further for different materials such as Inconel 617. [PERSON] et al. conducted experiments on the impact of Al2O3 nanofluids in coconut oil on the cutting of Inconel 617 [11]. [PERSON]'s L9 orthogonal array was used to effectively vary the MQL concentration, cutting velocity, and feed rate. Using this methodology, it was found that the tool wear and surface roughness decreased with a lower cutting speed and higher concentration of MQL nanofluid. The existing research on the machining of Inconel 617, however, has not highlighted the influence of the machining process on the subsurface of the material in terms of the work hardening levels and its effect on tool wear. Characterizing the material hardening behaviour after machining will allow improvements in the machining productivity and quality of nuclear components in Gen IV reactor manufacturing. [PERSON] et al. conducted experiments to optimize the end-milling of Inconel 617 [12]. Their work provided insights into the machinability of the alloy as well as baseline parameters used to improve the machinability in the turning of Inconel 617. Their work focused on optimizing the material removal rate (MRR); however, the authors did not use a coolant in the design or factor in the state of the machined material in terms of the work hardening and residual stresses associated with pressure and temperature. It is beneficial to understand the impact of coolants on the machining of Inconel 617 with these parameters. A summary of the related works used in the literature review of Inconel 617 and 718 has been included in Table 1.  
Inconel 617 is classified as a hard-to-machine material. This is due to its tendency to work harden, the presence of abrasive precipitates causing large amounts of tool wear on the flank and rake faces, and high hot hardness [11]. These properties reduce tool life during a conventional machining process such as in turning, milling, and drilling. Work hardening is caused by the intense plastic deformation of the material that occurs in machining such that it alters the hardness and brittleness properties [21].