Journal Article

Influence of binder systems on sintering characteristics, microstructures, and mechanical properties of PcBN composites fabricated by SPS

Chen, Shuna, Zhang, Yongsheng, Li, Jicheng, Song, Junjie, Fan, Hengzhong, Li, Wensheng, Hu, Litian, Su, Yunfeng, Yan, Bing

2022

Overview

Cubic boron nitride (cBN) with high hardness, thermal conductivity, wear resistance, and chemical inertness has become the most promising abrasive and machining material. Due to the difficulty of fabricating pure cBN body, generally, some binders are incorporated among cBN particles to prepare polycrystalline cubic boron nitride (PcBN). Hence, the binders play a critical factor to the performances of PcBN composites. In this study, the PcBN composites with three binder systems containing ceramic and metal phases were fabricated by spark plasma sintering (SPS) from 1400 to 1700 °C. The sintering behaviors and mechanical properties of the composites were investigated. Results show that the effect of binder formulas on mechanical properties mainly related to the compactness, mechanical performances, and thermal expansion coefficient of binder phases, which affect the carrying capacity of the composites and the bonding strength between binder phases and cBN particles. The PcBN composite with SiAlON phase as binder presented optimal flexural strength (465±29 MPa) and fracture toughness (5.62±0.37 MPa·m 1/2 ), attributing to the synergistic effect similar to transgranular and intergranular fractures. Meanwhile, the excellent mechanical properties can be maintained a comparable level when the temperature even rises to 800 °C. Due to the weak bonding strength and high porosity, the PcBN composites with Al 2 O 3 -ZrO 2 (3Y) and Al-Ti binder systems exhibited inferior mechanical properties. The possible mechanisms to explain these results were also analyzed.

• Publisher: Tsinghua University Press,Springer
• Subject: Abrasive machining / Abrasive wear / Aluminum oxide / Analysis / binder system / Bonding strength / Boron nitride / Carrying capacity / Ceramics / Characterization and Evaluation of Materials / Chemistry and Materials Science / Composites / Cubic boron nitride / Flexural strength / fracture mechanism / Fracture toughness / Glass / Hardness / high temperature mechanical property / Intergranular fracture / Machining / Materials Science / Mechanical properties / Nanotechnology / Natural Materials / Particulate composites / Phases / Plasma sintering / polycrystalline cubic boron nitride (PcBN) / Porosity / Research Article / Sintering / Sintering (powder metallurgy) / sintering characteristic / Spark plasma sintering / Structural Materials / Synergistic effect / Thermal conductivity / Thermal expansion / Thermal properties / Thermal resistance / Titanium / Wear resistance / Zirconium dioxide