Microstructure Alterations of Ti-6Al-4V ELI during Turning by Using Tungsten Carbide Inserts under Dry Cutting Condition

Ibrahim G.A., Arinal H., . Zulhanif, Haron C.H.C.

Abstract


Titanium alloys possesses a hexagonal close packed
(h.c.p) structure, called phase to ambient temperature. This
structure changes to body center cubic (b.c.c), called phase to
the temperature of 882 C. Machining process that generates high
temperature during machining can affect on microstructures of
machined surface, which represents as a quality of components.
The turning parameters evaluated are cutting speed (55 - 95
m/min), feed rate (0.15 - 0.35 mm/rev), depth of cut (0.10 - 0.20
mm) and tool grade (uncoated, CVD and PVD). The aims of this
paper are to investigate the effects of machining process on
microstructures of machined surface and chip were machined
using tungsten carbide inserts under dry cutting condition. The
results show that machining at high cutting speed (95 m/min)
affected on the microstructure significantly at the end of
machining. The temperature is the most significant factor
affected on microstructure of the machined surface and chip at
shear zone. The changes of microstructure were also affected by
the tool pressure during cutting.


Keywords


Ti-6Al-4V ELI; microstructure; alteration; turning; carbide insert

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References


Boyer,R.R.,(1995). “Titanium for aerospace: rationale and application” Material Science and Engineering, pp. 349-368.

Che Haron, C.H.,(2001).“Tool life and surface integrity in turning titanium alloy,” Journal of Material Processing and Technology, pp. 3449-368.

Che Haron , C.H., and A. Jawaid, (2005).“The effect of machining on surface integrity of titanium alloy Ti-6%Al-4%V,” Journal of Materials Processing Technology, pp. 188-192.

Ezugwu, E.O., J. Booney, B, Rosemar, Da Silva and O. Cakir, (2007).“Surface integrity of finished turned Ti-6Al-4V alloy with PCD tools using conventional and high pressure coolant supplies.” International Journal of Machine Tools and Manufacture, pp. 884-891.

Ezugwu,E.O , J. Booney, and Y. Yamane, (2003)“An overview of the machinability of aero engine alloys,” Journal of Material Processing and Technology, pp. 233-253.

Ezugwu,E.O.(2005)“Key improvement in the machining of difficult-to-cut aerospace Super alloys,” International Journal of Machine Tools & Manufacture, pp. 1353-1367.

Ezugwu, E.O., R.B. Da Silva, J. Bonney and A.R. Machado, (2005)“Evaluation of the performance of CBN tools when turning Ti-6Al-4V alloy with high pressure coolant supplies,” Journal of Machine Tools and Manufacture , pp. 1009-1014.

Gifkins ,R.C.(1978).“Comments on theories of structural superplasticity,” Materials Science and Engineering, pp. 27-33.

Jawaid, A., C.H. Che Haron and A. Abdullah,(1999). “„Tool wear characteristics in turning of titanium alloy Ti-6246,” Journal Material Processing and Technology, pp. 329-334.

Jawaid, A., S. Sharif and S. Koksal,(2001). “Evaluation of wear mechanism of coated carbide tools when face milling titanium alloy,” Journal of Material Processing and Technology, pp. 266-274.

Kim, S.W., D.W. Lee, M.C. Kang and J.S. Kim,(2001). ”Evaluation of machinability by cutting environments in high-speed milling of difficult-to-cut materials,” Journal of Material Processing and Technology, pp. 256-260.

Leyens, C., and M. Peters,(2003). „Titanium and Titanium Alloys: Fundamentals and Applications’ Weinheim: Willey VCH.

Massalski, T.B.,(1986). “Binary Alloys Phase Diagram,” American Society Metallurgy, pp.173.

Novovic, D., R.C. Dewes, D.K. Aspinwall and P.B. Voice, (2004).“The effect of machined topography and integrity on fatigue life” International Journal of Machined Tools & Manufacture, pp. 125-134.

Polmear,I.J.(1981). “Light Alloys: Metallurgy of the Light Metal‟ London: Edward Arnold Publisher.

Ribeiro, M.V., M.R.V. Moreira and J.R. Ferreira,(2003). “Optimization of titanium alloy (6Al-4V) machining,” Journal of Material Processing and Technology, pp. 458-463.