Thermal Behavior of Single-Crystal Diamonds Catalyzed by Titanium Alloy at Elevated Temperature

Pengyu Hou,Ming Zhou,Haijun Zhang

doi:10.3390/app10134651

Pengyu Hou, Ming Zhou + Show 1 more

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https://doi.org/10.3390/app10134651

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Abstract

Single-crystal diamonds are considered as the best tool material for ultra-precision machining. However, due to its low thermal conductivity, small elastic modulus and strong chemical activity, titanium alloy has poor machinability and is a typically difficult-to-machine material. Excessive tool wear prevents diamonds from cutting titanium alloy. This study conducts a series of thermal analytic experiments under conditions of different gas atmospheres in order to research the details of thermochemical wear of diamonds catalyzed by titanium alloy at elevated temperatures. Raman scattering analysis was performed to identify the transformation of the diamond crystal structure. The change in chemical composition of the work material was detected be means of energy dispersive X-ray analysis. X-ray photoelectron spectroscopy was used to confirm the resultant interfacial thermochemical reactions. The results of the study reveal the diffusion law of the single-crystal diamond under the action of titanium in the argon and air environment. From the experimental results, the product of the chemical reaction corresponding to the interface between the diamond and the titanium alloy sheet could be found. The research results provide a theoretical basis for elucidating the wear mechanism of diamond tools in the titanium alloy cutting process and for exploring the measures to suppress tool wear.

Highlights

Single-crystal diamonds are often used in ultra-precision machining for components where an optical-grade surface finishes Are generally required
The carbon atoms in Ti alloy-cutting with the diamond tool diffuse into the titanium alloy workpiece on the tool/work contact interface in diamond-cutting of titanium alloys
In the process of Ti alloy-cutting with diamond tool, the wear of the diamond tool can be summarized as follows: (1) In absence of oxygen at high temperatures of the cutting zone and the catalysis of titanium atoms, the carbon atoms in the single-crystal diamond tool escape from the crystal lattice of the diamond and transform into a graphite structure

Summary

Introduction

Single-crystal diamonds are often used in ultra-precision machining for components where an optical-grade surface finishes Are generally required. It is difficult to machine due to elevated cutting forces, high temperature, limited cutting conditions and excessive tool wear [1]. Thin-wall structures are usually manufactured out of aluminum and titanium alloys and are widely used in the aeronautical sector. Their machining presents serious challenges such as vibrations because of excessive tool wear and high cutting force [2]. The concentrated heat in the cutting zone has a negative influence on the tool life [3]. Polvorosa carried out an experimental to study the effect of lubricant pressure and material heat treatment on cutting forces and tool wear evolution on turning of super alloys [4].

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