Comparative Analysis of the Machinability of Various Titanium Alloys
Titanium alloys have a good strength to weight ratio, amazing corrosion resistance. These alloys are mostly used in the aerospace, biomedical and automotive industries. However, titanium alloys are difficult to machine since they are chemically reactive and have low thermal conductivity. Drilling is an important machining process with titanium alloys since it is used is most titanium applications. The machinability of titanium alloys varies depending on the method the titanium alloy was manufactured. There is a lack of knowledge for drilling additive manufactured titanium and powdered metallurgy titanium. This study will investigate and compare the wear of various drill bits with various manufactured titanium alloys using a constant feed rate and cutting speed. The titanium alloys used include the reference alloy of Ti-6Al-4V, powder metallurgy titanium and additive manufactured titanium. The drill bits used include high speed steel drill bits, three flute carbide drill bits and coated carbide drill bits. Additionally, the torque is recorded to analyze the drilling performance for each experiment. The drill bit tips, the drilled holes, and the drilled in the workpiece, and the drilled chips were studied microscopically to determine the wear rate of the drill bits, the material transfer, the quality of the drilled surfaces, and the ease of chip dejection. The additive manufactured titanium showed promising material properties but the machinability aspect showed that the wear was poor compared to the reference Ti-6Al-4V alloy.
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