Influence of the cutting material on tool wear, surface roughness, and force components for different cutting speeds in face turning of CoCrFeNi high-entropy alloys

Abstract

High-entropy alloys (HEAs) provide advanced properties like a high resistance to corrosion and wear. Concerning this and the elevated material costs wear protection layers are a possible field of application. Finish machining of these layers is necessary to achieve adequate surface properties. In the experimental investigations face turning of high-entropy alloy CoCrFeNi layers generated by spark plasma sintering is regarded. In this context, the influence of the cutting material and the cutting speed is analysed. For this, CBN tipped (two types), PCD tipped, CVD diamond tipped, and solid cemented carbide indexable inserts are used. Additionally, the influence of four different cutting speeds in the range between 100 m/min and 400 m/min is analysed. The feed and the depth of cut are kept constant with 0.05 mm and 0.1 mm, respectively. The geometrical surface properties are determined by tactile measurements and 3D laser scanning microscopy. The tool wear is analysed microscopically. Regarding the surface roughness, CBN tipped tools with a high content of boron nitride lead to the best results with the lowest roughness values irrespective of the cutting speed. The tool wear is also significantly reduced compared to the other cutting materials tested. The investigations represent the first results analysing the influence of the cutting material in machining of high-entropy alloys. Hence, this contributes to the enhancement of the field of application of HEAs.

Influence of Milling Conditions on AlxCoCrFeNiMoy Multi-Principal-Element Alloys

“…However, for potential applications, it is still necessary to bridge the gap regarding processability, since publications in this matter are scarce, hence the importance of researching, for example, machining processes on these novel alloys. So far, research on the machinability of HEA systems is limited [18][19][20][21][22][23], with the majority focusing on the Cantor alloy. Gou et al [18] conducted a study on different machining processes on the Cantor alloy, including milling, grinding, mechanical polishing, electrodischarge machining, and electropolishing.…”

“…They reported a high affection of the subsurface in terms of high microhardness and compressive residual stresses for the milling process. Liborius et al [21] investigated the influence of the tool material (CBN, PCD, CVD diamond, and solid cemented carbide) and cutting speed (100-400 m/min) in the face turning of SPS-fabricated CoCrFeNi, reporting the lowest roughness values and tool wear for CBN 90 tips. Litwa et al [22] investigated the effect of depth of cut, feed per cutting edge, and cutting speed on the Cantor alloy, observing reduced cutting forces at a low depth of cut and feed rate and at high cutting speeds.…”

On the WEDM of WNbMoTaZrx (x = 0.5, 1) Refractory High Entropy Alloys

“…The high strength and low thermal of the Ti alloys often cause a high cutting temperature, which significantly influences the machined surface quality and tools lifetime [ 18 ]. Studies on the conventional machining of HEAs have shown that although a good surface quality can be achieved, the lifetime of cutting tools was significantly reduced due to numerous cutting heat and severe wear [ 19 , 20 , 21 ]. While for the RHEAs with a higher strength and hardness, how to process RHEAs is more challenging but important for their engineering applications.…”