SiCw对WC-ZrO2材料微观组织及力学性能的影响  

Effect of SiCw on the Microstructure and Mechanical Properties of WC-ZrO2

作　　者：陈国清[1,2] 任媛媛 付雪松 周文龙[1,2] CHEN Guo-Qing;REN Yuan-Yuan;FU Xue-Song;ZHOU Wen-Long(Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province),School of Materials Science and Engineering,Dalian University of Technology,Dalian 116085,China)

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116085 [2]辽宁省凝固控制与数字化制备技术重点实验室,辽宁大连116085

出　　处：《现代技术陶瓷》2019年第3期191-198,共8页Advanced Ceramics

基　　金：国家国际科技合作专项(2015DFR60370);航空科学基金(20153663010);中央高校基本科研业务费(DUT17GF209)

摘　　要：采用热压烧结工艺制备了WC-ZrO2-SiCw复合材料,研究了SiCw含量对材料微观组织和力学性能的影响。结果表明,随着SiCw含量增加,材料平均晶粒尺寸先增大后降低,其中WC-ZrO2-2%SiCw的晶粒尺寸为0.55μm。在WC-ZrO2-4%SiCw中出现了m-ZrO2相,这是晶粒尺寸过大和晶须热膨胀系数较小共同作用的结果。随着SiCw含量增加,由于晶粒粗化以及过量的晶须缠绕会产生孔洞等缺陷,复合材料硬度呈现先降低后略微上升的趋势,其中WC-ZrO2-4%SiCw的硬度最低,仅为17.8GPa。断裂韧性随SiCw含量的变化先升高后降低,其中WC-ZrO2-2%SiCw的断裂韧性最高,较未添加SiCw的WC-ZrO2提高了12.3%,这是因为SiCw的添加引起裂纹偏转、穿晶断裂和裂纹桥接,从而起到增韧效果。烧结态WC-ZrO2-2%SiCw致密度可达到99.4%,其断裂韧性和硬度分别为9.12MPa·m^1/2和18.5GPa。WC-ZrO2-SiCw composites were prepared by hot pressing. The effect of SiCw content on the microstructure and the mechanical properties of composites were studied. The results showed that the average grain size increases at first and then declines with increase of SiCw content. The average grain size of WC-ZrO2-2%SiCw is 0.55 μm. Due to excessive grain growth and small thermal expansion coefficient of SiCw, there is m-ZrO2 in WC-ZrO2-4%SiCw. With the increasing of SiCw content, hardness declines dramatically and then picks up slightly because of coarse grains and pores. The hardness of WC-ZrO2-4%SiCw is only 17.8 GPa, which is the lowest in all the samples investigated. Fracture toughness increases firstly and then decreases with the increase of SiCw content. Compared to WC-ZrO2, the fracture toughness of WC-ZrO2-2%SiCw is improved by 12.3% and is the highest one. The reasons of high fracture toughness are crack deflection, transgranular fracture and crack bridging caused by the adding of SiCw. The relative density of sintered WC-ZrO2-2%SiCw is 99.4% and its fracture toughness and hardness is 9.12 MPa·m^1/2 and 8.5 GPa, respectively.

关 键 词：WC-ZrO2-SiCw 微观组织 力学性能 裂纹偏转 

分 类 号：TF1[冶金工程—冶金物理化学]