# Influence of Cutting Parameters and MQL on Surface Finish and Work Hardening of Inconel 617
## 2 Related Works
In machining, increased hardness at  
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**Authors** & **Material** & **Process** & **Major Findings** & **Reference** \\ \hline [PERSON]; [PERSON] & Inconel 718 & Influence of cutting parameters on work hardening behaviour of surface layer during turning superalloy Inconel 718 & * Cutting speed and feed rate had high impact on work hardening of Inconel 718 & Cutting speed and feed rate had high impact on work hardening of Inconel 718 & Cutting speed and feed rate had high impact on work hardening of Inconel 718 & Cutting speed increased the hardness but decrease the depth of hardness & Cutting speed increased the hardness but decrease the depth of hardness & Cutting speed increased the hardness but decrease the depth of hardness & Cutting speed shortened tool life drastically and increased surface roughness & Cutting speed & Cutting speed & Cutting speed & Cutting speed & Cutting speed & Cutting speed & & & & & \\ \hline [PERSON]; [PERSON]; [PERSON] & Inconel 718 & Finish-turning with MQL and various tool coatings & * Cutting speed shortened tool life drastically and increased surface roughness & * Cutting speed shortened tool life drastically and increased surface roughness & Cutting speed shortened tool life drastically and increased surface roughness & Cutting speed shortened tool life drastically and increased surface roughness & Cutting speed increased the cooling of the contact regions & Cutting speed and fixed rate had high impact on work hardening of Inconel  
the surface of a workpiece may contribute to large rates of notch wear in the tool due to high abrasion at the location of the depth of cut. This may contribute to tool failure and a poor surface finish [22]. Large notches occurring on the tool can induce large stress concentrations when machining, leading to higher rates of tool fracture and part failure. Furthermore, Inconel 617 contains abrasive particles that are present in the form of hardened carbide precipitates occurring between and within the grains of the microstructure. These contribute to excessive flank wear on the tool as the hardened particles strip away at the tool during machining. Tool wear can lead to geometrical inaccuracies in the generated workpiece as the flank of the tool reduces in size [23]. To reduce tool wear, tool coatings are often added to improve the durability of the tool. The tool coating acts as a barrier between the workpiece and the tool, creating a hardened tool surface to withstand abrasion while maintaining the toughness and durability of the tool substrate. This is a commonly used and widely researched method of reducing tool wear in hard-to-machine materials such as Inconel 718 [24]. Tool wear also leads to a poor surface finish caused by the adhesion of the workpiece material onto the exposed substrate of the tool, causing a built-up edge (BUE) to form [25]. This BUE is a hardened piece of Inconel that becomes welded onto the tool edge due to the high pressures and temperatures that occur at the tool nose caused by the cut. BUE formation may result in the overcutting of the workpiece, leading to geometrical inaccuracies and large gouges in the generated surface. BUE breakage will leave deposits on the surface and form large burrs that cause a poor surface finish. This breakage can also lead to tool fracture, chipping, and the rapid failure of the tool and machined part as the adhered material may become harder than the tool substrate itself [26; 27; 28]. Another method to improve the machining of Inconel is the addition of a coolant. A coolant is used to reduce the temperature at the location of the cut as well as provide lubrication to the contact points, thus decreasing the level of tool wear and the likelihood of a BUE formation. In conventional machining applications, a water-oil emulsification is deposited via nozzle jets as a flood coolant to rapidly remove heat and flush chips away from the machining contact point.