Microscopic Observation of the Interface between a Tool Wear Surface and Deposits from a Low Carbon Free Cutting Steel Machined

作者：Matsui Naoki^*; Sano Naoyuki; Fujiwara Junsuke; Ohishi Keiichiro; Ohkubo Tadakatsu; Hono Kazuhiro

来源：Journal of the Japan Institute of Metals, 2011, 75(9): 516-523.

• tool wear
• machining
• wear mechanism
• laser-assisted three-dimensional atom probe
• free cutting steel

Microstructures and element distribution at the interface between a worn tool surface and a residue of low carbon cutting steel, which was left behind and accumulated on the tool surface during its machining, were observed and analyzed by transmission electron microscopy (TEM) and laser assisted three dimensional atom probe tomography (LA3DAP). The residue of the machined steel was composed of fine ferrite grains a few hundred nanometers in size, which were considered to be a result of a grain refinement process by severe plastic deformation. Tungsten carbide (WC) particles embedded in the tool were sharply worn out at the interface, thus the interface was found to be flat and sharp in nanometers scale. Since the deposited steel on the worn tool surface was so tightly bound that the interface was successfully analyzed by LA3DAP in transverse direction. It was shown that tungsten atoms from the WC particles had diffused into the deposited steel with a distance of approximately 10 nm from the interface. It has been suggested that the tool wear upon machining low carbon cutting steels proceeds mainly by the diffusion of tool component elements into the deposited iron, in which accelerated diffusion occurs due to the fast diffusion paths created by severe plastic strains introduced during machining.

• 出版日期2011-9