摘要
以B4C、SiC粗粉为原料,采用机械合金化辅助热压烧结工艺,在不添加任何助烧剂的情况下于1950℃制备出致密的B4C-SiC复合陶瓷。通过对烧结样品进行相对密度、维氏硬度、抗弯强度和断裂韧性测试,研究SiC含量对复合陶瓷力学性能的影响;结合XRD、SEM和TEM对样品进行组分和微观结构分析,研究其微观结构与力学性能之间的关系。结果表明:复合陶瓷的相对密度和断裂韧性随SiC含量的增加而增大,当SiC含量为50wt%时获得最大值为96.1%和4.6 MPa·m1/2;复合陶瓷的硬度和抗弯强度随SiC含量的增加呈先增大后减小的趋势,在SiC含量为20wt%时获得最大值25.5 GPa和480 MPa。SiC相均匀分布在B4C基体中使得复合陶瓷具有较高的强度;B4C与SiC之间好的界面相容性以及SiC的高断裂韧性是该B4C基复合陶瓷韧性得到显著提高的原因。
Dense B4C-SiC composite ceramics were fabricated through mechanical alloying using coarser B4C and SiC powders as starting powders, and subsequent hot pressing sintering at 1950℃ without any sintering aid. The in- fluences of the content of SiC on mechanical properties of the composite ceramics were studied through determining relative density of composite ceramics, Vickers hardness, flexure strength and fracture toughness. Combined with the microstructure and component analysis technologies ofXRD, SEM and TEM, the relationship between microstructure and mechanical properties of the composite ceramics was investigated. The results indicate that the relative density and fracture toughness of the composite ceramics are improved with increase of SiC content, and reach the maximum value at 96.1% and 4.6 MPa.ml/2,respectively, with SiC content of 50wt%. However, with the increase of SiC, the Vickers hardness and flexure strength are enhanced firstly and then decreased. The maximum values are 25.5 GPa and 480 MPa, respectively, with SiC content of 20wt%. Homogeneous dispersion of SiC phase in B4C matrix is one of the reasons why the composite ceramics possess higher flexure strength. Fracture toughness of the composite ceramics is significantly higher than that of monomeric B4C. The main reasons are attributed to powerful interfacial bonding be- tween B4C and SiC as well as the higher fracture toughness of SiC.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第7期695-700,共6页
Journal of Inorganic Materials
基金
中日韩A3前瞻计划项目(51161140399)
国家自然科学基金(U12301013)~~
关键词
复合陶瓷
热压
机械合金化
力学性能
微观结构
composite ceramics
hot pressing
mechanical alloying
mechanical properties
microstructure
