Fracture Properties of PCBN as a Function of Loading Rate and Temperature

Abstract:

Polycrystalline Cubic Boron Nitride (PCBN) is a super-hard material used in some of the most demanding material removal operations today. These include turning of hardened steels, as well as the machining of highly abrasive alloys. In these applications the tools are subjected to high operating temperatures, abrasive and impact loading. This can lead to the brittle fracture of the tool. Accurate determination of the fracture toughness and mechanical properties of PCBN under a wide range of operating conditions is therefore essential in order to evaluate the performance of the tool under these highly demanding conditions. For this study, a laboratory scale three point bend test rig has been used for the fracture tests. The fracture toughness of two different grades of PCBN are measured at a range of loading rates and temperatures corresponding to the actual in-service conditions. The results show the measured properties of these materials vary with both loading rate and temperature. The fracture surfaces of the specimens are examined using scanning electron microscopy to determine dominant fracture mechanisms.

• Periodical: Key Engineering Materials (Volumes 452-453)
• Pages: 457-460
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.452-453.457
• Online since: November 2010
• Authors: Declan Carolan, Marin Petrović, Alojz Ivanković, Neal Murphy
• Keywords: Fracture, High Rate, PCBN

References

[1] Fleming, M.A., Bossom, P.K., 2000. PCBN - performance goals for the 21st century, Industrial Diamond Review.

[2] Carolan, D., Petrovic, M., Ivankovic, A., Murphy, N., 2009. Key Engineering Materials 417, 669-672.

[3] Carolan, D., Petrovic, M., Ivankovic, A., 2009. Mechanical and Fracture Properties of PCBN as a function of rate and temperature. In: Proceedings of the 6th ICCSM, Dubrovnik, Croatia.

[4] Advanced Technical Ceramics - Test methods for determination of fracture toughness of monolithic ceramics, Part 5, Single-edge vee notch beam (SEVNB) method (CEN 144255: 2004). British Standards Institute.

DOI: 10.3403/03224656u

[5] Kalthoff, J.F. 1985. On the measurement of dynamic fracture toughness - a review of recent work. International Journal of Fracture 27, 277-298.

DOI: 10.1007/bf00017973

[6] Carslaw, H.S., Jaeger, J.G., 1959. Conduction of heat in solids (2nd Ed. ) London: Oxford University Press Acknowledgements The authors gratefully acknowledge the support of Enterprise Ireland, IRCSET and Element 6 Ltd., Shannon, Ireland.