摘要
Abstract
Hexagonal boron nitride(h-BN)ceramics are significant in industrial applications,however,their special layered structure,combined with low strength and hardness,limits their application.In this study,ytterbium aluminum silicate(YbAS)glass and hard SiC particles were simultaneously introduced as reinforcing phases,and a series of h-BN/YbAS/SiC composites were prepared by in-situ reaction hot pressing sintering techniques.With the volume fraction of YbAS glass fixed at 30%,the effect of SiC content on the properties of the composites was studied.The results demonstrate that the synergistic effect of YbAS glass and SiC can effectively enhance the strength and toughness of h-BN-based composites.This composite exhibits optimal mechanical performance when the SiC volume fraction reaches 30%,yielding flexural strength,compressive strength,fracture toughness,Vickers hardness,and elastic modulus values of(462±5)MPa,(1465±58)MPa,(5.5±0.3)MPa·m1/2,(4.7±0.3)GPa,and 140 GPa,respectively.The strengthening mechanism is identified as when the SiC content reaches a certain proportion,it plays a supporting role,effectively bearing external loads to enhance the composites.Moreover,SiC can effectively suppress the growth of h-BN grains during the sintering process,contributing to fine-grained strengthening.The composites also have good high-temperature mechanical properties and relatively low thermal conductivity,with the thermal expansion coefficient being related to structure of h-BN and transition temperature of YbAS glass.This study provides an effective approach for the strengthening and toughening of h-BN ceramic materials.关键词
h-BN基复合材料/YbAS玻璃/SiC/力学性能/热学性能Key words
h-BN-based composite/YbAS glass/SiC/mechanical property/thermal property分类
化学化工
