Derivative cutting is a texture-edge cutting of chip bottom side, which happens all the time in machining with textured tools. Two new types of textured tools are developed and fabricated: a micro-textured tool with chamfered texture edge (CTE) tool and a multiscale textured (MSTT) tool with the texture surface below the rake face. The effectiveness of the tools on inhibiting derivative cutting is investigated at different cutting velocities. For the CTE tool, the inhibiting effect is more pronounced with the increase in the chamfer angle, but the severe rake face wear eventually leads to the occurrence of derivative cutting. Compared with the CTE tool, the multiscale textures of the MSTT tool provide more sustainable effectiveness in inhibiting derivative cutting. The inhibition mechanisms of the two types of textured tools are discussed.

To reveal the wear mechanisms of TiAlN, TiAlSiN, and CrAlN coatings in a seawater environment, the changes in frictional surfaces and the electrochemical characteristics of these coatings were compared and analyzed in this paper. The coatings were deposited on 316L stainless steel surfaces. Tribological tests were investigated using a ball-on-disk tribometer with Si₃N₄ ceramic balls as the counter material. Although the friction coefficient of 316L stainless steel was the lowest at 0.34, the order of wear rates was 316L stainless steel (7.38 × 10⁻⁵) > TiAlN(5.31 × 10⁻⁶) > TiAlSiN(4.23 × 10⁻⁶) > CrAlN(1.10 × 10⁻⁶) and the electrochemical protective efficiencies of TiAlSiN and CrAlN were both greater than 97%. Seawater penetrated through the grain boundaries of the TiAlN coating, which led to corrosion and delamination failure. Conversely, the grain refinement in TiAlSiN and CrAlN coatings can significantly slow down the penetration of seawater into the coating under frictional pressure, and the oxide lubricating layer formed during the friction process can become an effective barrier to isolate seawater. Therefore, mechanical wear was the main wear form of these two coatings. Additionally, among the oxides formed in the friction, Cr₂O₃ showed the strongest corrosion resistance, making the CrAlN coating exhibit superior wear resistance and the lowest wear rate in seawater.

Severe friction and extreme temperatures occur at the tool–chip interface during metal cutting. Conventional cutting fluids struggle to penetrate interface micro-capillaries at the contact interface under high contact pressure. This issue causes severe tool–chip adhesion and accelerates tool wear. This study aims to solve fluid delivery limitations by introducing micro-textures with a depth of 15 microns on the tool surfaces. It reveals the mechanism of micro-textures in accelerating fluid penetration and reducing interface friction. An analytical capillary penetration model was established for conventional and micro-textured tools. Thermal penetration tests (30–150 °C) and turning experiments on hardened steel were conducted to evaluate interfacial fluid transport behavior. Theoretical modeling shows that micro-textures facilitate direct vapor-phase filling into micro-capillaries. This mechanism bypasses liquid ingress and droplet evaporation stages. This reduces the fluid penetration time into the capillaries by almost an order of magnitude. Thermal tests show that textured surfaces maintain dynamic vapor–liquid equilibrium. At 150 °C, the vapor penetration area reaches 978.5 × 10⁻³ mm² on micro-textures, over four times that of smooth surfaces. Energy dispersive spectrometry (EDS) detected fluid-derived sodium (0.98 at.%) inside micro-textured capillaries. Meanwhile, workpiece material adhesion decreases from 6.04 at.% to 0.11 at.%. In turning tests of AISI 1045 hardened carbon steel, micro-textured tools reduced the main cutting force by up to 17% and the axial force by up to 22%. Cutting temperatures decreased by up to 10.0%. The average tool–chip friction coefficient dropped by 9.2% at a cutting speed of 240 m/min. This work provides insights into a vapor-phase lubrication mechanism and offers quantitative guidance for designing high-efficiency self-lubricating tools.