High pressure sintering behavior and mechanical properties of cBN–Ti₃Al and cBN–Ti₃Al-Al composite materials

Abstract

The sintering behavior and mechanical properties of cubic boron nitride (cBN) composites, using the mixture of cBN–Ti₃Al and cBN–Ti₃Al-Al as the starting material respectively, were investigated under high pressure and high temperature (HPHT) conditions. The results show that the samples of cBN–Ti₃Al-Al sintering system have more homogeneous microstructures. Young's modulus, shear modulus, and bulk modulus of samples measured by ultrasonic measurements can reach to 782±3 GPa, 344±1 GPa, and 348±2 GPa, respectively. The hardness increases remarkably with the sintering temperature rising, and reaches to the highest value of 35.04±0.51 GPa. For the cBN–Ti₃Al sintering system, the X-ray diffraction patterns of composites reveal that the chemical reactions between cBN and Ti₃Al occurred at 5.0 GPa and 1300°C. The reaction mechanisms of both cBN–Ti₃Al and cBN–Ti₃Al-Al sintering systems are discussed in this paper.

Keywords:

• cubic boron nitride (cBN)
• high pressure high temperature (HPHT) sintering
• hardness
• microstructure
• elasticity modulus

Acknowledgements

This work was funded by Sichuan University, National Natural Science Foundation of China (Grant No. 51072123) and Key Laboratory of Shock Wave and Detonation Physics Foundation (Grant. No. 9140C670201110C6703).