ZrB_(2)-SiC/Zr-Al-C复合材料的制备与性能

Preparation and Properties of ZrB_(2)-SiC/Zr-Al-C Composites

采用放电等离子烧结技术(SPS)制备原位自生纳米层状Zr-Al-C相改性ZrB_(2)-SiC复合材料,研究不同烧结温度对纳米层状Zr-Al-C相改性ZrB_(2)-SiC复合材料的物相组成、微观结构和力学性能的影响,并探讨材料的强韧化机制.结果表明:在1500,1600,1700℃烧结温度下,均原位合成了纳米层状Zr-Al-C相,厚度在几十纳米到几百纳米之间;烧结温度从1500℃升高到1700℃时,复合材料的断裂韧性由(4.51±0.04)MPa·m^(1/2)提高至(5.04±0.02)MPa·m^(1/2),维氏硬度由(7.3±1.1)GPa提高至(14.2±1.1)GPa,断裂韧性和维氏硬度分别提高约12%和95%;随着烧结温度的升高,试样的致密度提高,气孔减少,晶粒间结合更紧密,断裂韧性和维氏硬度都逐渐增大.

ZrB_(2)-SiC composites modified by nano-layered Zr-Al-C phase are prepared by spark plasma sintering(SPS).The effects of different sintering temperatures on the phase composition,microstructure and mechanical properties of ZrB_(2)-SiC composites modified by nano-layered Zr-Al-C phase are investigated,and the strengthening and toughening mechanism of the composites is also discussed.Results show that nano-layered Zr-Al-C phase is in situ synthesized at 1500,1600 and 1700℃,and the thickness ranges from tens to hundreds of nanometers.With the increase of sintering temperature from 1500℃to 1700℃,the fracture toughness of the composites increases from(4.51±0.04)MPa·m^(1/2)to(5.04±0.02)MPa·m^(1/2),the hardness increases from(7.3±1.1)GPa to(14.2±1.1)GPa,which are increased by about 12%and 95%respectively.With the increase of sintering temperature,the density of the sample increases,the porosity decreases,and the bonding between grains is closer.Therefore,the fracture toughness and hardness increase gradually.