摘要
通过热压烧结制备SiC(W)-ZrO2-MoSi2复相陶瓷,利用X射线衍射仪、图像分析仪、透射电镜对复相陶瓷试样组织结构进行了研究,探讨了SiC(W)-ZrO2协同作用对MoSi2陶瓷性能的影响。结果表明:纳米ZrO2颗粒的加入对材料的细化作用较SiC晶须明显,复相协同作用细化效果更好。SiC(W)-ZrO2协同作用的综合机制有利于提高复相陶瓷的抗弯强度和断裂韧性,ZrO2量的增加对提高复相陶瓷断裂韧性的作用更明显;ZrO2粒子钉扎位错,导致可动位错绕过,强化材料基体。弥散分布的SiC晶须阻碍位错运动,使位错缠结、交割,阻碍晶界迁移;粒子周围出现孪晶以及SiC晶须引起的层错,阻碍其晶粒长大。
SiC（W）-ZrO2-MoSi2 ceramic composites were prepared by hot-pressing sintering.Microstructure of the composites was investigated by means of X-ray diffraction （XRD）,image analysis and transmission electron microscopy （TEM）.The synergic effect of SiC（W）-ZrO2 on mechanical preperties of MoSi2 ceramics was discussed.The results show that the effect of ZrO2 nanoparticles on refing the matrix is more obvious than that of SiC whiskers,and the better refing effect of synergism by SiC（W） and ZrO2 nanoparticles is observed.The synergism of SiC（W）-ZrO2 is more favorable to enhance bending strength and fracture toughness of the composite ceramics.The addtion of ZrO2 for improving fracture toughness of the composites is more obvious compared with the addtion of SiC.The pining effect of ZrO2 particles on dislocations induces the moving dislocations around the particles and strengthens matrix.The disperse SiC whisker obstructs dislocation movement,causing tangle and intersecting of dislocations and blocking the migration of grain boundary.Moreover,twins formed around ZrO2 particles and stacking faults around SiC whiskers hinder the growth of grain.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2010年第8期10-14,共5页
Transactions of Materials and Heat Treatment
基金
航空基础科学基金项目(04G56008)
江西省自然科学基金项目(2009GZC0107)
