Microstructural and mechanical properties of cBN-Si composites prepared from the high pressure infiltration method

作者：Liu, Yinjuan; He, Duanwei^*; Wang, Pei; Yan, Xiaozhi; Xu, Chao; Liu, Fangming; Liu, Jin; Hu, Qiwei

来源：International Journal of Refractory Metals and Hard Materials, 2016, 61: 1-5.

DOI：10.1016/j.ijrmhm.2016.07.020

• cBN
• Silicon
• High pressure
• Infiltration sintering
• Grain size

The grain size dependence of the mechanical properties of cBN-Si composites prepared using the high pressure infiltration method has been investigated. Indentation testing indicates that cBN-Si composites have hardness values of 38-43 GPa, which increase with increasing grain size and are harder than traditional polycrystalline cBN composites (PcBNs). Thermostability analyses display that cBN-Si composites with a grain size of >9 mu m also possess a higher temperature of oxidation, compared to traditional PcBNs, and the thermostability increases with increasing cBN grain size. Fracture toughness tests show that almost no cracks appear on the polished cBN-Si samples when the loading forces are increased to 294 N and the fracture toughness is better than for commercial samples. Scanning electron microscopy illustrates that deformations and close pores occurred easily between coarse BN grains, leading to denser cBN-Si compacts with better mechanical performances.

• 出版日期2016-12
• 单位四川大学