纳米SiC晶须和SiC颗粒混合增韧ZrB_2陶瓷性能

Properties of ZrB_2 ceramics reinforced by SiC nanowhiskers and SiC particles

分别采用纳米SiC晶须(SiCW)、SiC颗粒(SiCP)及SiCW与SiCP共同增韧ZrB2陶瓷,在1950℃、20 MPa压力、氩气气氛下热压烧结制备了致密的SiC/ZrB2陶瓷材料。研究了SiCW和SiCP的添加量对于SiC/ZrB2陶瓷材料的显微结构、力学性能的影响,并分析了SiCW和SiCP对ZrB2陶瓷力学性能影响的协同作用和增韧机制。结果表明:含15 vol%SiCW的复合材料的韧性达到8.08 MPa.m1/2,含15 vol%SiCP的复合材料的韧性达到8.515MPa.m1/2,共同添加15 vol%SiCW和15 vol%SiCP的复合材料的韧性最高达到9.03 MPa.m1/2。SiC/ZrB2复合材料强度和韧性提高的原因在于SiCW和SiCP抑制ZrB2晶粒长大,促进ZrB2的致密化,此外,SiCW和SiCP的协同作用也有助于材料韧性的提高。

SiC/ZrB2 composites reinforced by SiC nanowhiskers（SiCw） and SiC particles（SiCe） were prepared by a hot pressing process at 1950℃ under 20 MPa in a flow argon atmosphere. The effects of SiCw and SiCp on microstruetures, mechanical properties of SiC/ZrB2 composites were investigated. The results showed that the fracture toughnesses of SiC/ZrB2 composites with 15 vol% of SiCw and with 15 vol% of SiCe were 8.08 MPa-m1/2 and 8. 515 MPa.m1/2 , respectively. The fracture toughness of the SiC/ZrB2 composites with both 15 vol% of SiCw and 15 vol% of SiCe reached 9.03 MPa. m1/2. SiCw and SiCe effectively improved the densification of SiC/ZrB2 composites, and limited the coarsening of ZrB2 grains, which was in favor of improving the bending strength and fracture toughness of the SiC/ZrB2 composites. Furthermore, the synergistic effect of SiCw and SiCe favored the increase of the toughness.