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Densification and mechanical properties of boron carbide prepared via spark plasma sintering with cubic boron nitride as an additive
Journal of the European Ceramic Society ( IF 5.8 ) Pub Date : 2019-12-24 , DOI: 10.1016/j.jeurceramsoc.2019.12.047
Jinchang Sun , Bo Niu , Lin Ren , Jinyong Zhang , Liwen Lei , Fan Zhang

Hexagonal boron nitride (h-BN) can reinforce boron carbide (B4C) ceramics, but homogeneous dispersion of h-BN is difficult to achieve using conventional methods. Herein, B4C/h-BN composites were manufactured via the transformation of cubic (c-) BN during spark plasma sintering at 1800 °C. The effects of the c-BN content on the microstructure, densification, and mechanical properties of B4C/h-BN composites were evaluated. In situ synthesized h-BN platelets were homogeneously dispersed in the B4C matrix and the growth of B4C grains was effectively suppressed. Moreover, the c-BN to h-BN phase transformation improved the sinterability of B4C. The sample with 5 vol.% c-BN exhibited excellent integrated mechanical properties (hardness of 30.5 GPa, bending strength of 470 MPa, and fracture toughness of 3.84 MPa⋅ m1/2). Higher c-BN contents did not significantly affect the bending strength and fracture toughness but clearly decreased the hardness. The main toughening mechanisms were crack deflection, crack bridging, and pulling out of h-BN.



中文翻译:

立方氮化硼作为添加剂通过火花等离子体烧结制备的碳化硼的致密化和力学性能

六方氮化硼(h -BN)可以增强碳化硼(B 4 C)陶瓷,但是使用常规方法很难实现h -BN的均匀分散。在此,通过在1800℃下的火花等离子体烧结过程中立方(c-)BN的转变来制造B 4 C / h -BN复合材料。评估了c -BN含量对B 4 C / h -BN复合材料的微观结构,致密化和力学性能的影响。原位合成的h -BN血小板均匀分散在B 4中C基体和B 4 C晶粒的生长得到有效抑制。此外,Ç -BN到ħ -BN相变改善B的烧结4 C的样品与5体积%Ç -BN表现出30.5吉帕优良综合机械性能(硬度,弯曲470兆帕的强度,和断裂韧性3.84MPa·m 1/2的压力。较高的c -BN含量并未显着影响弯曲强度和断裂韧性,但明显降低了硬度。主要的增韧机制是裂纹挠曲,裂纹桥接和从h -BN中拉出。

更新日期:2019-12-24
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