Tool wear is a problem in machining titanium alloy, so it is of great importance to find out the wear mechanism of cutting tools in order to improve the cutting tool life time. The mechanism controlling the wear of cemented carbide and influence of cutting parameters on different wear modes in machining Ti6Al4V has been investigated in this paper. Diffusion and chemical wear at high cutting speed and feed rate and attrition in low speed and feed rate is suggested to be the dominant wear mechanism in this case.
1. Introduction
Titanium shows a high strength-weight ratio and has exceptional corrosion resistance. Titanium alloys have received considerable interest recently due to their wide range of applications in the aerospace, automotive and medical industries. The most common titanium alloy is Ti6Al4V, which belongs to the α+ β alloy group. However titanium alloys are difficult to machine due to their low modules of elasticity. Titanium is a poor conductor of heat, its thermal conductivity is about 1/6 that of steel. Heat, generated by the cutting action, does not dissipate quickly; therefore, most of the heat is concentrated on the cutting edge and the tool face [1]. Titanium has a strong alloying tendency or chemical reactivity with materials in the cutting tools and also reacts with oxygen and nitrogen in air at tool operating temperatures. This causes galling, welding, and smearing along with rapid destruction of the cutting tool [1].
The element diffusion from the tool through the tool-chip interface leads to composition change of tool substrate, which may increase the possibility of mechanical damage of the cutting edge also the high strength of titanium at elevated temperature contributes to the high compressive stresses ...
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...ay crater and flank wear in combination with chipping and cracking along the cutting edge.
• At low cutting conditions attrition was found dominant wear mechanism of cemented carbide cutting tool.
• At severe cutting condition by increasing the temperature, mechanism of tool wear involve diffusion.
• The brittle failure is due to high contact stresses at the cutting edge due to a combination of critical cutting parameters. The weak cutting edge du to the crate also contributes to the brittle failure.
• Plastic deformation can also be a major contributor to wear mechanisms of cutting tool when machining titanium alloys
• High compressive stresses and the development of high temperature close to the cutting edge causes plastic deformation of cutting edge
• The tendency for chipping and micro fracture along the cutting edge increases with feed rate and cutting speed.
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