HP-HT sintering, microstructure, and properties of B6O- and TiC-containing composites based on cBN

Abstract

The article presents a study of the potential for the use of B 6 O superhard boron suboxide as a binder in composite materials with a low cBN content. Superhard B 6 O is characterized by higher mechan ical properties than TiC widely used in commercial materials today. Composites containing 60 vol % cBN and different binder compositions that included B 6 O and TiC have been sintered in a toroid type high pressure apparatus at a pressure of 7.7 GPa in a temperature range from 1500 to 2000°C. The microstruc ture, phase and elemental composition of the sintered materials have been examined via electron micros copy and X ray diffraction analysis. Mechanical properties have been analyzed via indentation techniques. The performance of the cutting tools produced from the sintered composites has been evaluated in turning hardened cold work tool steel.

Performance and wear mechanisms of novel superhard diamond and boron nitride based tools in machining Al-SiCp metal matrix composite

“…3). [14]. High hardness of the material is combined with rather low fracture toughness (KIC = 4.7 MPa·m 1/2 ) and low thermal conductivity of k = 14 W/(m·K) [14].…”

“…[14]. High hardness of the material is combined with rather low fracture toughness (KIC = 4.7 MPa·m 1/2 ) and low thermal conductivity of k = 14 W/(m·K) [14]. Round inserts RNGN090300E15 with nominal edge radius of 15 µm were placed on CRSNL3225P09 toolholder, which provided -6° back and -6° side rake angles.…”

Compositions, mechanical properties and microstructures of cBN-based composites sintered with Al or TiC

“…Microstructures and mechanical properties of cBN-TiC composites were also investigated and a two-step sintering process was proposed to improve the mechanical properties [10]. Recently, cBN-based composites were prepared from cBN-TiC composites at 7.7 GPa and 2000°C, with the formation of Ti(C, N) and TiB 2 [11].…”